/**
* Initializes the shader system. Creates a 1x1 texture that can be used as a fallback texture when framebuffer support is missing.
* Also compiles the shaders used for particle rendering.
*/
void opengl_shader_init()
{
glGenTextures(1,&Framebuffer_fallback_texture_id);
GL_state.Texture.SetActiveUnit(0);
GL_state.Texture.SetTarget(GL_TEXTURE_2D);
GL_state.Texture.Enable(Framebuffer_fallback_texture_id);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
GLuint pixels[4] = {0,0,0,0};
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 1, 1, 0, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, &pixels);
GL_shader.clear();
// Reserve 32 shader slots. This should cover most use cases in real life.
GL_shader.reserve(32);
// compile effect shaders
gr_opengl_maybe_create_shader(SDR_TYPE_EFFECT_PARTICLE, 0);
gr_opengl_maybe_create_shader(SDR_TYPE_EFFECT_PARTICLE, SDR_FLAG_PARTICLE_POINT_GEN);
gr_opengl_maybe_create_shader(SDR_TYPE_EFFECT_DISTORTION, 0);
gr_opengl_maybe_create_shader(SDR_TYPE_SHIELD_DECAL, 0);
// compile deferred lighting shaders
opengl_shader_compile_deferred_light_shader();
// compile passthrough shader
opengl_shader_compile_passthrough_shader();
mprintf(("\n"));
}
/**
* Initializes the shader system. Creates a 1x1 texture that can be used as a fallback texture when framebuffer support is missing.
* Also compiles the shaders used for particle rendering.
*/
void opengl_shader_init()
{
if ( !Use_GLSL ) {
return;
}
glGenTextures(1,&Framebuffer_fallback_texture_id);
GL_state.Texture.SetActiveUnit(0);
GL_state.Texture.SetTarget(GL_TEXTURE_2D);
GL_state.Texture.Enable(Framebuffer_fallback_texture_id);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
GLuint pixels[4] = {0,0,0,0};
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 1, 1, 0, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, &pixels);
if (Cmdline_no_glsl_model_rendering) {
Use_GLSL = 1;
}
GL_shader.clear();
// Reserve 32 shader slots. This should cover most use cases in real life.
GL_shader.reserve(32);
// Compile the particle shaders, since these are most definitely going to be used
opengl_compile_main_shader(SDR_FLAG_SOFT_QUAD);
opengl_compile_main_shader(SDR_FLAG_SOFT_QUAD | SDR_FLAG_DISTORTION);
mprintf(("\n"));
}
/**
* Pass a GLSL shader source to OpenGL and compile it into a usable shader object.
* Prints compilation errors (if any) to the log.
* Note that this will only compile shaders into objects, linking them into executables happens later
*
* @param shader_source GLSL sourcecode for the shader
* @param shader_type OpenGL ID for the type of shader being used, like GL_FRAGMENT_SHADER_ARB, GL_VERTEX_SHADER_ARB
* @return OpenGL handle for the compiled shader object
*/
GLhandleARB opengl_shader_compile_object(const SCP_vector<SCP_string>& shader_source, GLenum shader_type)
{
GLhandleARB shader_object = 0;
GLint status = 0;
SCP_vector<const GLcharARB*> sources;
sources.reserve(shader_source.size());
for (auto it = shader_source.begin(); it != shader_source.end(); ++it) {
sources.push_back(it->c_str());
}
shader_object = vglCreateShaderObjectARB(shader_type);
vglShaderSourceARB(shader_object, sources.size(), &sources[0], NULL);
vglCompileShaderARB(shader_object);
// check if the compile was successful
vglGetObjectParameterivARB(shader_object, GL_OBJECT_COMPILE_STATUS_ARB, &status);
opengl_shader_check_info_log(shader_object);
// we failed, bail out now...
if (status == 0) {
// basic error check
mprintf(("%s shader failed to compile:\n%s\n", (shader_type == GL_VERTEX_SHADER_ARB) ? "Vertex" : ((shader_type == GL_GEOMETRY_SHADER_EXT) ? "Geometry" : "Fragment"), GLshader_info_log));
// this really shouldn't exist, but just in case
if (shader_object) {
vglDeleteObjectARB(shader_object);
}
return 0;
}
// we succeeded, maybe output warnings too
if (strlen(GLshader_info_log) > 5) {
nprintf(("SHADER-DEBUG", "%s shader compiled with warnings:\n%s\n", (shader_type == GL_VERTEX_SHADER_ARB) ? "Vertex" : ((shader_type == GL_GEOMETRY_SHADER_EXT) ? "Geometry" : "Fragment"), GLshader_info_log));
}
return shader_object;
}