duuqnd/cave-story-solaris
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Use orphaning to slightly speed up rendering GPU-side

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For some reason CPU usage is still double that of the SDLTexture
backend (SDL2 uses OpenGL 2.1, with glEnable/glDisable-style
immediate mode).

If I downgrade to OpenGL 2.1, and use VBO-less glDrawArrays, I get
great performance. I just wish I knew what the AMD driver is doing
that's so much faster.
This commit is contained in:
Clownacy 2019-08-09 16:25:36 +01:00
parent 5712c4ad63
commit 4afe7f4b11
1 changed files with 4 additions and 5 deletions
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9
src/Backends/Rendering/OpenGL3.cpp
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@ -255,7 +255,6 @@ BOOL Backend_Init(SDL_Window *p_window)
// Set up Vertex Buffer Object
glGenBuffers(1, &vertex_buffer_id);
glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer_id);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertex_buffer), NULL, GL_STREAM_DRAW);
// Set up the vertex attributes
glEnableVertexAttribArray(1);
@ -348,7 +347,7 @@ void Backend_DrawScreen(void)
vertex_buffer.vertexes[3].x = -1.0f;
vertex_buffer.vertexes[3].y = 1.0f;
glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(vertex_buffer), &vertex_buffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertex_buffer), &vertex_buffer, GL_STREAM_DRAW);
glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
SDL_GL_SwapWindow(window);
@ -462,7 +461,7 @@ static void BlitCommon(Backend_Surface *source_surface, const RECT *rect, Backen
vertex_buffer.vertexes[3].x = vertex_left;
vertex_buffer.vertexes[3].y = vertex_bottom;
glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(vertex_buffer), &vertex_buffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertex_buffer), &vertex_buffer, GL_STREAM_DRAW);
glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
}
@ -511,7 +510,7 @@ static void ColourFillCommon(Backend_Surface *surface, const RECT *rect, unsigne
vertex_buffer.vertexes[3].x = vertex_left;
vertex_buffer.vertexes[3].y = vertex_bottom;
glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(vertex_buffer.vertexes), &vertex_buffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertex_buffer), &vertex_buffer, GL_STREAM_DRAW);
glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
}
@ -641,7 +640,7 @@ static void DrawGlyphCommon(Backend_Surface *surface, Backend_Glyph *glyph, long
vertex_buffer.vertexes[3].x = vertex_left;
vertex_buffer.vertexes[3].y = vertex_bottom;
glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(vertex_buffer), &vertex_buffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertex_buffer), &vertex_buffer, GL_STREAM_DRAW);
if (glyph->pixel_mode == FONT_PIXEL_MODE_LCD)
{