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My first OpenGL shader! Momma will be so proud!

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This shader implements the software renderer mask semantics where the source pixel is multiplied by the color and alpha modulation values and then any pixel with non-zero alpha is fully opaque.

The OpenGL renderer on Mac OS X now passes all the automated render tests! :)
This commit is contained in:
Sam Lantinga
2009-11-21 05:29:31 +00:00
parent 3808553966
commit 58effb88d3
1 changed files with 53 additions and 5 deletions
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58
src/video/SDL_renderer_gl.c
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@@ -175,6 +175,7 @@ typedef struct
PFNGLPROGRAMSTRINGARBPROC glProgramStringARB;
/* (optional) fragment programs */
GLuint fragment_program_mask;
GLuint fragment_program_UYVY;
} GL_RenderData;
@@ -484,6 +485,17 @@ power_of_2(int input)
//#define DEBUG_PROGRAM_COMPILE 1
static void
set_shader_error(GL_RenderData * data, const char *prefix)
{
GLint pos = 0;
const GLubyte *errstr;
data->glGetIntegerv(GL_PROGRAM_ERROR_POSITION_ARB, &pos);
errstr = data->glGetString(GL_PROGRAM_ERROR_STRING_ARB);
printf("%s: shader compile error at position %d: %s",
prefix, (int) pos, (const char *) errstr);
}
static GLuint
compile_shader(GL_RenderData * data, GLenum shader_type, const char *_code)
{
@@ -541,6 +553,18 @@ compile_shader(GL_RenderData * data, GLenum shader_type, const char *_code)
}
/*
* Fragment program that implements mask semantics
*/
static const char *fragment_program_mask_source_code = "!!ARBfp1.0\n"
"OUTPUT output = result.color;\n"
"TEMP value;\n"
"TEX value, fragment.texcoord[0], texture[0], %TEXTURETARGET%;\n"
"MUL value, fragment.color, value;\n"
"SGE value.a, value.a, 0.001;\n"
"MOV output, value;\n"
"END";
/*
* Fragment program that renders from UYVY textures.
* The UYVY to RGB equasion is:
@@ -751,7 +775,7 @@ GL_CreateTexture(SDL_Renderer * renderer, SDL_Texture * texture)
compile_shader(renderdata, GL_FRAGMENT_PROGRAM_ARB,
fragment_program_UYVY_source_code);
if (renderdata->fragment_program_UYVY == 0) {
SDL_SetError("Fragment program compile error");
set_shader_error(renderdata, "UYVY");
return -1;
}
}
@@ -1162,6 +1186,7 @@ GL_RenderCopy(SDL_Renderer * renderer, SDL_Texture * texture,
{
GL_RenderData *data = (GL_RenderData *) renderer->driverdata;
GL_TextureData *texturedata = (GL_TextureData *) texture->driverdata;
GLuint shader = 0;
int minx, miny, maxx, maxy;
GLfloat minu, maxu, minv, maxv;
@@ -1215,6 +1240,23 @@ GL_RenderCopy(SDL_Renderer * renderer, SDL_Texture * texture,
GL_SetBlendMode(data, texture->blendMode, 0);
/* Set up the shader for the copy, we have a special one for MASK */
shader = texturedata->shader;
if (texture->blendMode == SDL_BLENDMODE_MASK && !shader) {
if (data->fragment_program_mask == 0) {
data->fragment_program_mask =
compile_shader(data, GL_FRAGMENT_PROGRAM_ARB,
fragment_program_mask_source_code);
if (data->fragment_program_mask == 0) {
/* That's okay, we'll just miss some of the blend semantics */
data->fragment_program_mask = ~0;
}
}
if (data->fragment_program_mask != ~0) {
shader = data->fragment_program_mask;
}
}
if (texture->scaleMode != data->scaleMode) {
switch (texture->scaleMode) {
case SDL_TEXTURESCALEMODE_NONE:
@@ -1235,9 +1277,9 @@ GL_RenderCopy(SDL_Renderer * renderer, SDL_Texture * texture,
data->scaleMode = texture->scaleMode;
}
if (texturedata->shader != 0) {
if (shader) {
data->glEnable(GL_FRAGMENT_PROGRAM_ARB);
data->glBindProgramARB(GL_FRAGMENT_PROGRAM_ARB, texturedata->shader);
data->glBindProgramARB(GL_FRAGMENT_PROGRAM_ARB, shader);
}
data->glBegin(GL_TRIANGLE_STRIP);
@@ -1251,7 +1293,7 @@ GL_RenderCopy(SDL_Renderer * renderer, SDL_Texture * texture,
data->glVertex2f(0.5f + maxx, 0.5f + maxy);
data->glEnd();
if (texturedata->shader != 0) {
if (shader) {
data->glDisable(GL_FRAGMENT_PROGRAM_ARB);
}
@@ -1377,7 +1419,13 @@ GL_DestroyRenderer(SDL_Renderer * renderer)
if (data->GL_ARB_fragment_program_supported) {
data->glDisable(GL_FRAGMENT_PROGRAM_ARB);
data->glBindProgramARB(GL_FRAGMENT_PROGRAM_ARB, 0);
if (data->fragment_program_UYVY != 0) {
if (data->fragment_program_mask &&
data->fragment_program_mask != ~0) {
data->glDeleteProgramsARB(1,
&data->fragment_program_mask);
}
if (data->fragment_program_UYVY &&
data->fragment_program_UYVY != ~0) {
data->glDeleteProgramsARB(1,
&data->fragment_program_UYVY);
}