407 lines
11 KiB
C++
407 lines
11 KiB
C++
// Released under the MIT licence.
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// See LICENCE.txt for details.
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#include "../Rendering.h"
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#include <stddef.h>
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#include <stdlib.h>
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#include <string.h>
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#include "../Misc.h"
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#include "Window/Software.h"
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#include "../../Attributes.h"
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#define MIN(a, b) ((a) < (b) ? (a) : (b))
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#define MAX(a, b) ((a) > (b) ? (a) : (b))
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typedef struct RenderBackend_Surface
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{
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unsigned char *pixels;
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size_t width;
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size_t height;
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size_t pitch;
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} RenderBackend_Surface;
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typedef struct RenderBackend_GlyphAtlas
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{
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unsigned char *pixels;
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size_t width;
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size_t height;
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} RenderBackend_GlyphAtlas;
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static RenderBackend_Surface framebuffer;
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static RenderBackend_GlyphAtlas *glyph_atlas;
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static RenderBackend_Surface *glyph_destination_surface;
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static unsigned char glyph_colour_channels[3];
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RenderBackend_Surface* RenderBackend_Init(const char *window_title, size_t screen_width, size_t screen_height, bool fullscreen)
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{
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if (WindowBackend_Software_CreateWindow(window_title, screen_width, screen_height, fullscreen))
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{
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framebuffer.pixels = WindowBackend_Software_GetFramebuffer(&framebuffer.pitch);
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framebuffer.width = screen_width;
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framebuffer.height = screen_height;
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return &framebuffer;
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}
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else
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{
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Backend_PrintError("Failed to create window");
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}
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return NULL;
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}
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void RenderBackend_Deinit(void)
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{
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WindowBackend_Software_DestroyWindow();
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}
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void RenderBackend_DrawScreen(void)
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{
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WindowBackend_Software_Display();
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// Backends may use double-buffering, so fetch a new framebuffer just in case
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framebuffer.pixels = WindowBackend_Software_GetFramebuffer(&framebuffer.pitch);
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}
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RenderBackend_Surface* RenderBackend_CreateSurface(size_t width, size_t height, bool render_target)
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{
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(void)render_target;
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RenderBackend_Surface *surface = (RenderBackend_Surface*)malloc(sizeof(RenderBackend_Surface));
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if (surface == NULL)
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return NULL;
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surface->pixels = (unsigned char*)malloc(width * height * 4);
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if (surface->pixels == NULL)
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{
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free(surface);
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return NULL;
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}
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surface->width = width;
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surface->height = height;
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surface->pitch = width * 4;
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return surface;
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}
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void RenderBackend_FreeSurface(RenderBackend_Surface *surface)
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{
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free(surface->pixels);
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free(surface);
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}
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bool RenderBackend_IsSurfaceLost(RenderBackend_Surface *surface)
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{
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(void)surface;
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return false;
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}
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void RenderBackend_RestoreSurface(RenderBackend_Surface *surface)
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{
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(void)surface;
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}
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void RenderBackend_UploadSurface(RenderBackend_Surface *surface, const unsigned char *pixels, size_t width, size_t height)
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{
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for (size_t y = 0; y < height; ++y) {
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int srcl = y * width * 3;
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int dstl = y * surface->pitch;
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for (size_t x = 0; x < width; ++x) {
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int srcr = x * 3;
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int dstr = x * 4;
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#ifdef LITTLE_ENDIAN
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surface->pixels[dstl + dstr + 0] = pixels[srcl + srcr + 2];
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surface->pixels[dstl + dstr + 1] = pixels[srcl + srcr + 1];
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surface->pixels[dstl + dstr + 2] = pixels[srcl + srcr + 0];
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#else
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surface->pixels[dstl + dstr + 1] = pixels[srcl + srcr + 2];
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surface->pixels[dstl + dstr + 2] = pixels[srcl + srcr + 1];
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surface->pixels[dstl + dstr + 3] = pixels[srcl + srcr + 0];
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#endif
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}
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}
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}
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ATTRIBUTE_HOT void RenderBackend_Blit(RenderBackend_Surface *source_surface, const RenderBackend_Rect *rect, RenderBackend_Surface *destination_surface, long x, long y, bool colour_key)
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{
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RenderBackend_Rect rect_clamped;
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rect_clamped.left = rect->left;
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rect_clamped.top = rect->top;
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rect_clamped.right = rect->right;
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rect_clamped.bottom = rect->bottom;
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// Clamp the rect and coordinates so we don't write outside the pixel buffer
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long overflow;
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overflow = 0 - x;
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if (overflow > 0)
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{
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rect_clamped.left += overflow;
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x += overflow;
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}
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overflow = 0 - y;
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if (overflow > 0)
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{
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rect_clamped.top += overflow;
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y += overflow;
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}
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overflow = (x + (rect_clamped.right - rect_clamped.left)) - destination_surface->width;
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if (overflow > 0)
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rect_clamped.right -= overflow;
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overflow = (y + (rect_clamped.bottom - rect_clamped.top)) - destination_surface->height;
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if (overflow > 0)
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rect_clamped.bottom -= overflow;
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if (rect_clamped.bottom - rect_clamped.top <= 0)
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return;
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if (rect_clamped.right - rect_clamped.left <= 0)
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return;
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// Do the actual blitting
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if (colour_key)
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{
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for (long j = 0; j < rect_clamped.bottom - rect_clamped.top; ++j)
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{
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const unsigned char *source_pointer = &source_surface->pixels[((rect_clamped.top + j) * source_surface->pitch) + (rect_clamped.left * 4)];
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unsigned char *destination_pointer = &destination_surface->pixels[((y + j) * destination_surface->pitch) + (x * 4)];
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for (long i = 0; i < rect_clamped.right - rect_clamped.left; ++i)
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{
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#ifdef LITTLE_ENDIAN
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register char red = source_pointer[0];
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register char green = source_pointer[1];
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register char blue = source_pointer[2];
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#else
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register char red = source_pointer[1];
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register char green = source_pointer[2];
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register char blue = source_pointer[3];
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#endif
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if (UNLIKELY(red == 0 && green == 0 && blue == 0)) // Assumes the colour key will always be #000000 (black)
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{
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source_pointer += 4;
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destination_pointer += 4;
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}
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else
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{
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#ifdef LITTLE_ENDIAN
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*destination_pointer++ = *source_pointer++;
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*destination_pointer++ = *source_pointer++;
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*destination_pointer++ = *source_pointer++;
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destination_pointer++;
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source_pointer++;
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#else
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destination_pointer++;
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source_pointer++;
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*destination_pointer++ = *source_pointer++;
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*destination_pointer++ = *source_pointer++;
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*destination_pointer++ = *source_pointer++;
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#endif
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}
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}
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}
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}
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else
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{
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const unsigned char *source_pointer = &source_surface->pixels[(rect_clamped.top * source_surface->pitch) + (rect_clamped.left * 4)];
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unsigned char *destination_pointer = &destination_surface->pixels[(y * destination_surface->pitch) + (x * 4)];
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for (long j = 0; j < rect_clamped.bottom - rect_clamped.top; ++j)
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{
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memcpy(destination_pointer, source_pointer, (rect_clamped.right - rect_clamped.left) * 4);
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source_pointer += source_surface->pitch;
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destination_pointer += destination_surface->pitch;
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}
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}
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}
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ATTRIBUTE_HOT void RenderBackend_ColourFill(RenderBackend_Surface *surface, const RenderBackend_Rect *rect, unsigned char red, unsigned char green, unsigned char blue)
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{
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RenderBackend_Rect rect_clamped;
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rect_clamped.left = rect->left;
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rect_clamped.top = rect->top;
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rect_clamped.right = rect->right;
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rect_clamped.bottom = rect->bottom;
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// Clamp the rect so it doesn't write outside the pixel buffer
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long overflow;
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overflow = 0 - rect_clamped.left;
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if (overflow > 0)
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rect_clamped.left += overflow;
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overflow = 0 - rect_clamped.top;
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if (overflow > 0)
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rect_clamped.top += overflow;
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overflow = rect_clamped.right - surface->width;
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if (overflow > 0)
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rect_clamped.right -= overflow;
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overflow = rect_clamped.bottom - surface->height;
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if (overflow > 0)
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rect_clamped.bottom -= overflow;
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if (rect_clamped.bottom - rect_clamped.top <= 0)
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return;
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if (rect_clamped.right - rect_clamped.left <= 0)
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return;
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for (long j = 0; j < rect_clamped.bottom - rect_clamped.top; ++j)
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{
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unsigned char *destination_pointer = &surface->pixels[((rect_clamped.top + j) * surface->pitch) + (rect_clamped.left * 4)];
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for (long i = 0; i < rect_clamped.right - rect_clamped.left; ++i)
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{
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#ifdef LITTLE_ENDIAN
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*destination_pointer++ = blue;
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*destination_pointer++ = green;
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*destination_pointer++ = red;
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destination_pointer++;
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#else
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destination_pointer++;
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*destination_pointer++ = blue;
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*destination_pointer++ = green;
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*destination_pointer++ = red;
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#endif
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}
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}
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}
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RenderBackend_GlyphAtlas* RenderBackend_CreateGlyphAtlas(size_t width, size_t height)
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{
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RenderBackend_GlyphAtlas *atlas = (RenderBackend_GlyphAtlas*)malloc(sizeof(RenderBackend_GlyphAtlas));
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if (atlas != NULL)
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{
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atlas->pixels = (unsigned char*)malloc(width * height);
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if (atlas->pixels != NULL)
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{
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atlas->width = width;
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atlas->height = height;
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return atlas;
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}
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free(atlas);
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}
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return NULL;
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}
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void RenderBackend_DestroyGlyphAtlas(RenderBackend_GlyphAtlas *atlas)
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{
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free(atlas->pixels);
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free(atlas);
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}
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void RenderBackend_UploadGlyph(RenderBackend_GlyphAtlas *atlas, size_t x, size_t y, const unsigned char *pixels, size_t width, size_t height, size_t pitch)
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{
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for (size_t i = 0; i < height; ++i) {
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memcpy(&atlas->pixels[(y + i) * atlas->width + x], &pixels[i * pitch], width);
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}
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}
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void RenderBackend_PrepareToDrawGlyphs(RenderBackend_GlyphAtlas *atlas, RenderBackend_Surface *destination_surface, unsigned char red, unsigned char green, unsigned char blue)
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{
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glyph_atlas = atlas;
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glyph_destination_surface = destination_surface;
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glyph_colour_channels[0] = red;
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glyph_colour_channels[1] = green;
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glyph_colour_channels[2] = blue;
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}
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void RenderBackend_DrawGlyph(long x, long y, size_t glyph_x, size_t glyph_y, size_t glyph_width, size_t glyph_height)
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{
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size_t surface_x;
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size_t surface_y;
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// Clamp to within the destination surface's boundaries
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if (x < 0)
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{
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surface_x = -x;
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if (surface_x >= glyph_width)
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return; // Glyph is offscreen to the left
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glyph_x += surface_x;
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glyph_width -= surface_x;
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}
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else
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{
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surface_x = x;
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}
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if (surface_x >= glyph_destination_surface->width)
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return; // Glyph is offscreen to the right
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if (glyph_width >= glyph_destination_surface->width - surface_x)
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glyph_width = glyph_destination_surface->width - surface_x;
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if (y < 0)
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{
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surface_y = -y;
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if (surface_y >= glyph_height)
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return; // Glyph is offscreen to the top
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glyph_y += surface_y;
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glyph_height -= surface_y;
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}
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else
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{
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surface_y = y;
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}
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if (surface_y >= glyph_destination_surface->height)
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return; // Glyph is offscreen to the bottom
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if (glyph_height >= glyph_destination_surface->height - surface_y)
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glyph_height = glyph_destination_surface->height - surface_y;
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// Do the actual drawing
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for (size_t iy = 0; iy < glyph_height; ++iy)
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{
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for (size_t ix = 0; ix < glyph_width; ++ix)
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{
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const unsigned char alpha_int = glyph_atlas->pixels[(glyph_y + iy) * glyph_atlas->width + (glyph_x + ix)];
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if (alpha_int != 0)
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{
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const float alpha = alpha_int / 255.0f;
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unsigned char *bitmap_pixel = &glyph_destination_surface->pixels[(surface_y + iy) * glyph_destination_surface->pitch + (surface_x + ix) * 4];
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for (unsigned int j = 0; j < 3; ++j)
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bitmap_pixel[j] = (unsigned char)((glyph_colour_channels[j] * alpha) + (bitmap_pixel[j] * (1.0f - alpha))); // Alpha blending
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}
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}
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}
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}
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void RenderBackend_HandleRenderTargetLoss(void)
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{
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// No problem for us
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}
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void RenderBackend_HandleWindowResize(size_t width, size_t height)
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{
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WindowBackend_Software_HandleWindowResize(width, height);
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}
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