diff options
Diffstat (limited to 'gl.c')
| -rw-r--r-- | gl.c | 128 |
1 files changed, 128 insertions, 0 deletions
@@ -0,0 +1,128 @@ +#include "lib/glcorearb.h" + +// macro trickery to avoid having to write everything twice +#define gl_for_each_proc(do)\ + do(CREATESHADER, CreateShader)\ + do(DELETESHADER, DeleteShader)\ + do(CREATEPROGRAM, CreateProgram)\ + do(SHADERSOURCE, ShaderSource)\ + do(GETSHADERIV, GetShaderiv)\ + do(GETSHADERINFOLOG, GetShaderInfoLog)\ + do(COMPILESHADER, CompileShader)\ + do(CREATEPROGRAM, CreateProgram)\ + do(DELETEPROGRAM, DeleteProgram)\ + do(ATTACHSHADER, AttachShader)\ + do(LINKPROGRAM, LinkProgram)\ + do(GETPROGRAMIV, GetProgramiv)\ + do(GETPROGRAMINFOLOG, GetProgramInfoLog)\ + do(USEPROGRAM, UseProgram)\ + do(GETATTRIBLOCATION, GetAttribLocation)\ + do(GETUNIFORMLOCATION, GetUniformLocation)\ + do(GENBUFFERS, GenBuffers)\ + do(DELETEBUFFERS, DeleteBuffers)\ + do(BINDBUFFER, BindBuffer)\ + do(BUFFERDATA, BufferData)\ + do(VERTEXATTRIBPOINTER, VertexAttribPointer)\ + do(ENABLEVERTEXATTRIBARRAY, EnableVertexAttribArray)\ + do(DISABLEVERTEXATTRIBARRAY, DisableVertexAttribArray)\ + do(GENVERTEXARRAYS, GenVertexArrays)\ + do(BINDVERTEXARRAY, BindVertexArray)\ + do(UNIFORM1F, Uniform1f)\ + do(UNIFORM2F, Uniform2f)\ + do(UNIFORM3F, Uniform3f)\ + do(UNIFORM4F, Uniform4f)\ + do(UNIFORM1I, Uniform1i)\ + do(UNIFORM2I, Uniform2i)\ + do(UNIFORM3I, Uniform3i)\ + do(UNIFORM4I, Uniform4i)\ + do(UNIFORMMATRIX4FV, UniformMatrix4fv)\ + do(DEBUGMESSAGECALLBACK, DebugMessageCallback)\ + do(DEBUGMESSAGECONTROL, DebugMessageControl)\ + +#define gl_declare_proc(upper, lower) static PFNGL##upper##PROC gl##lower; +gl_for_each_proc(gl_declare_proc) +#undef gl_declare_proc + +// set by main() +static int gl_version_major; +static int gl_version_minor; + +static void gl_get_procs(void) { + #define gl_get_proc(upper, lower) gl##lower = (PFNGL##upper##PROC)SDL_GL_GetProcAddress("gl" #lower); + gl_for_each_proc(gl_get_proc) + #undef gl_get_proc +} + +// compile a GLSL shader +static GLuint gl_compile_shader(char const *code, GLenum shader_type) { + GLuint shader = glCreateShader(shader_type); + glShaderSource(shader, 1, &code, NULL); + glCompileShader(shader); + GLint status = 0; + glGetShaderiv(shader, GL_COMPILE_STATUS, &status); + if (status == GL_FALSE) { + char log[1024] = {0}; + glGetShaderInfoLog(shader, sizeof log - 1, NULL, log); + debug_println("Error compiling shader: %s", log); + return 0; + } + return shader; +} + +// link together GL shaders +static GLuint gl_link_program(GLuint *shaders, size_t count) { + GLuint program = glCreateProgram(); + if (program) { + for (size_t i = 0; i < count; ++i) { + if (!shaders[i]) { + glDeleteProgram(program); + return 0; + } + glAttachShader(program, shaders[i]); + } + glLinkProgram(program); + GLint status = 0; + glGetProgramiv(program, GL_LINK_STATUS, &status); + if (status == GL_FALSE) { + char log[1024] = {0}; + glGetProgramInfoLog(program, sizeof log - 1, NULL, log); + debug_println("Error linking shaders: %s", log); + glDeleteProgram(program); + return 0; + } + } + return program; +} + +static GLuint gl_compile_and_link_shaders(char const *vshader_code, char const *fshader_code) { + GLuint shaders[2]; + shaders[0] = gl_compile_shader(vshader_code, GL_VERTEX_SHADER); + shaders[1] = gl_compile_shader(fshader_code, GL_FRAGMENT_SHADER); + GLuint program = gl_link_program(shaders, 2); + if (shaders[0]) glDeleteShader(shaders[0]); + if (shaders[1]) glDeleteShader(shaders[1]); + if (program) { + debug_print("Successfully linked program %u.\n", program); + } + return program; +} + +static GLuint gl_attrib_loc(GLuint program, char const *attrib) { + GLint loc = glGetAttribLocation(program, attrib); + if (loc == -1) { + debug_print("Couldn't find vertex attribute %s.\n", attrib); + return 0; + } + return (GLuint)loc; +} + +static GLint gl_uniform_loc(GLuint program, char const *uniform) { + GLint loc = glGetUniformLocation(program, uniform); + if (loc == -1) { + debug_print("Couldn't find uniform: %s.\n", uniform); + return -1; + } + return loc; +} + + |