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Use specialised shaders for everything

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Saves us having to do a bunch of extra legwork (setting up the blank
default texture, setting the colour modifier to white, etc.), and
should improve performance.

While I was at it, I made the colour modifier a uniform, so it only
has to be set once per quad, rather than once per vertex.
This commit is contained in:
Clownacy 2019-07-31 03:39:30 +00:00
parent d9929a8e1f
commit a5fd0cebc0
1 changed files with 60 additions and 46 deletions
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106
src/Backends/Rendering/OpenGL2.cpp
View file

@ -27,40 +27,53 @@ typedef struct Backend_Glyph
static SDL_Window *window;
static SDL_GLContext context;
static GLuint normal_program_id;
static GLuint colour_key_program_id;
static GLuint program_texture;
static GLuint program_texture_colour_key;
static GLuint program_colour_fill;
static GLuint program_glyph;
static GLint uniform_colour_fill_colour;
static GLint uniform_glyph_colour;
static GLuint framebuffer_id;
static GLfloat vertex_buffer[4][2];
static GLfloat texture_coordinate_buffer[4][2];
static GLubyte colour_buffer[4][3];
static Backend_Surface framebuffer_surface;
static const GLchar *vertex_shader_source = " \
static const GLchar *vertex_shader_plain = " \
#version 120\n \
void main() \
{ \
gl_Position = gl_ModelViewMatrix * gl_Vertex; \
} \
";
static const GLchar *vertex_shader_texture = " \
#version 120\n \
void main() \
{ \
gl_FrontColor = gl_Color; \
gl_TexCoord[0] = gl_MultiTexCoord0; \
gl_Position = gl_ModelViewMatrix * gl_Vertex; \
} \
";
static const GLchar *fragment_shader_source_normal = " \
static const GLchar *fragment_shader_texture = " \
#version 120\n \
uniform sampler2D tex; \
void main() \
{ \
gl_FragColor = gl_Color * texture2D(tex, gl_TexCoord[0].st); \
gl_FragColor = texture2D(tex, gl_TexCoord[0].st); \
} \
";
static const GLchar *fragment_shader_source_colour_key = " \
static const GLchar *fragment_shader_texture_colour_key = " \
#version 120\n \
uniform sampler2D tex; \
void main() \
{ \
vec4 colour = gl_Color * texture2D(tex, gl_TexCoord[0].st); \
vec4 colour = texture2D(tex, gl_TexCoord[0].st); \
\
if (colour.xyz == vec3(0.0f, 0.0f, 0.0f)) \
discard; \
@ -69,6 +82,25 @@ void main() \
} \
";
static const GLchar *fragment_shader_colour_fill = " \
#version 120\n \
uniform vec4 colour; \
void main() \
{ \
gl_FragColor = colour; \
} \
";
static const GLchar *fragment_shader_glyph = " \
#version 120\n \
uniform sampler2D tex; \
uniform vec4 colour; \
void main() \
{ \
gl_FragColor = colour * texture2D(tex, gl_TexCoord[0].st); \
} \
";
static GLuint CompileShader(const char *vertex_shader_source, const char *fragment_shader_source)
{
GLint shader_status;
@ -147,29 +179,26 @@ BOOL Backend_Init(SDL_Window *p_window)
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_COLOR_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glVertexPointer(2, GL_FLOAT, 0, vertex_buffer);
glTexCoordPointer(2, GL_FLOAT, 0, texture_coordinate_buffer);
glColorPointer(3, GL_UNSIGNED_BYTE, 0, colour_buffer);
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
// Set up blank default texture (it seems to be black by default, which sucks for colour modulation)
const unsigned char white_pixel[3] = {0xFF, 0xFF, 0xFF};
glBindTexture(GL_TEXTURE_2D, 0);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB8, 1, 1, 0, GL_RGB, GL_UNSIGNED_BYTE, white_pixel);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
// Set up our shaders
normal_program_id = CompileShader(vertex_shader_source, fragment_shader_source_normal);
colour_key_program_id = CompileShader(vertex_shader_source, fragment_shader_source_colour_key);
program_texture = CompileShader(vertex_shader_texture, fragment_shader_texture);
program_texture_colour_key = CompileShader(vertex_shader_texture, fragment_shader_texture_colour_key);
program_colour_fill = CompileShader(vertex_shader_plain, fragment_shader_colour_fill);
program_glyph = CompileShader(vertex_shader_texture, fragment_shader_glyph);
if (normal_program_id == 0 || colour_key_program_id == 0)
if (program_texture == 0 || program_texture_colour_key == 0 || program_colour_fill == 0 || program_glyph == 0)
printf("Failed to compile shaders\n");
// Get shader uniforms
uniform_colour_fill_colour = glGetUniformLocation(program_colour_fill, "colour");
uniform_glyph_colour = glGetUniformLocation(program_glyph, "colour");
// Set up framebuffer (used for surface-to-surface blitting)
glGenFramebuffersEXT(1, &framebuffer_id);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, framebuffer_id);
@ -191,14 +220,16 @@ void Backend_Deinit(void)
{
glDeleteTextures(1, &framebuffer_surface.texture_id);
glDeleteFramebuffersEXT(1, &framebuffer_id);
glDeleteProgram(colour_key_program_id);
glDeleteProgram(program_glyph);
glDeleteProgram(program_colour_fill);
glDeleteProgram(program_texture_colour_key);
glDeleteProgram(program_texture);
SDL_GL_DeleteContext(context);
}
void Backend_DrawScreen(void)
{
// Disable colour-keying
glUseProgram(normal_program_id);
glUseProgram(program_texture);
// Target actual screen, and not our framebuffer
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
@ -214,10 +245,6 @@ void Backend_DrawScreen(void)
glBindTexture(GL_TEXTURE_2D, framebuffer_surface.texture_id);
colour_buffer[0][0] = colour_buffer[1][0] = colour_buffer[2][0] = colour_buffer[3][0] = 0xFF;
colour_buffer[0][1] = colour_buffer[1][1] = colour_buffer[2][1] = colour_buffer[3][1] = 0xFF;
colour_buffer[0][2] = colour_buffer[1][2] = colour_buffer[2][2] = colour_buffer[3][2] = 0xFF;
texture_coordinate_buffer[0][0] = 0.0f;
texture_coordinate_buffer[0][1] = 1.0f;
texture_coordinate_buffer[1][0] = 1.0f;
@ -304,7 +331,7 @@ static void BlitCommon(Backend_Surface *source_surface, const RECT *rect, long x
return;
// Switch to colour-key shader if we have to
glUseProgram(colour_key ? colour_key_program_id : normal_program_id);
glUseProgram(colour_key ? program_texture_colour_key : program_texture);
glBindTexture(GL_TEXTURE_2D, source_surface->texture_id);
@ -318,10 +345,6 @@ static void BlitCommon(Backend_Surface *source_surface, const RECT *rect, long x
const GLfloat vertex_top = (GLfloat)y;
const GLfloat vertex_bottom = (GLfloat)y + (rect->bottom - rect->top);
colour_buffer[0][0] = colour_buffer[1][0] = colour_buffer[2][0] = colour_buffer[3][0] = 0xFF;
colour_buffer[0][1] = colour_buffer[1][1] = colour_buffer[2][1] = colour_buffer[3][1] = 0xFF;
colour_buffer[0][2] = colour_buffer[1][2] = colour_buffer[2][2] = colour_buffer[3][2] = 0xFF;
texture_coordinate_buffer[0][0] = texture_left;
texture_coordinate_buffer[0][1] = texture_top;
texture_coordinate_buffer[1][0] = texture_right;
@ -370,15 +393,9 @@ static void ColourFillCommon(const RECT *rect, unsigned char red, unsigned char
if (rect->right - rect->left < 0 || rect->bottom - rect->top < 0)
return;
// Disable colour-keying
glUseProgram(normal_program_id);
glUseProgram(program_colour_fill);
// Use blank default texture, for a solid colour-fill
glBindTexture(GL_TEXTURE_2D, 0);
colour_buffer[0][0] = colour_buffer[1][0] = colour_buffer[2][0] = colour_buffer[3][0] = red;
colour_buffer[0][1] = colour_buffer[1][1] = colour_buffer[2][1] = colour_buffer[3][1] = green;
colour_buffer[0][2] = colour_buffer[1][2] = colour_buffer[2][2] = colour_buffer[3][2] = blue;
glUniform4f(uniform_colour_fill_colour, red / 255.0f, green / 255.0f, blue / 255.0f, 1.0f);
vertex_buffer[0][0] = (GLfloat)rect->left;
vertex_buffer[0][1] = (GLfloat)rect->top;
@ -504,8 +521,7 @@ void Backend_UnloadGlyph(Backend_Glyph *glyph)
static void DrawGlyphCommon(Backend_Glyph *glyph, long x, long y, const unsigned char *colours)
{
// Disable colour-keying
glUseProgram(normal_program_id);
glUseProgram(program_glyph);
glBindTexture(GL_TEXTURE_2D, glyph->texture_id);
@ -514,9 +530,7 @@ static void DrawGlyphCommon(Backend_Glyph *glyph, long x, long y, const unsigned
const GLfloat vertex_top = (GLfloat)y;
const GLfloat vertex_bottom = (GLfloat)y + glyph->height;
colour_buffer[0][0] = colour_buffer[1][0] = colour_buffer[2][0] = colour_buffer[3][0] = colours[0];
colour_buffer[0][1] = colour_buffer[1][1] = colour_buffer[2][1] = colour_buffer[3][1] = colours[1];
colour_buffer[0][2] = colour_buffer[1][2] = colour_buffer[2][2] = colour_buffer[3][2] = colours[2];
glUniform4f(uniform_glyph_colour, colours[0] / 255.0f, colours[1] / 255.0f, colours[2] / 255.0f, 1.0f);
texture_coordinate_buffer[0][0] = 0.0f;
texture_coordinate_buffer[0][1] = 0.0f;