// Copyright 2019-2020 David Robillard <d@drobilla.net> // SPDX-License-Identifier: ISC #ifndef EXAMPLES_SHADER_UTILS_H #define EXAMPLES_SHADER_UTILS_H #include "glad/glad.h" #include <stdio.h> #include <stdlib.h> #include <string.h> typedef struct { GLuint vertexShader; GLuint fragmentShader; GLuint program; } Program; static GLuint compileShader(const char* header, const char* source, const GLenum type) { const GLchar* sources[] = {header, source}; const GLint lengths[] = {(GLint)strlen(header), (GLint)strlen(source)}; GLuint shader = glCreateShader(type); glShaderSource(shader, 2, sources, lengths); glCompileShader(shader); int status = 0; glGetShaderiv(shader, GL_COMPILE_STATUS, &status); if (status == GL_FALSE) { GLint length = 0; glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &length); char* log = (char*)calloc(1, (size_t)length); glGetShaderInfoLog(shader, length, &length, log); fprintf(stderr, "error: Failed to compile shader (%s)\n", log); free(log); return 0; } return shader; } static void deleteProgram(Program program) { glDeleteShader(program.vertexShader); glDeleteShader(program.fragmentShader); glDeleteProgram(program.program); } static Program compileProgram(const char* headerSource, const char* vertexSource, const char* fragmentSource) { static const Program nullProgram = {0, 0, 0}; Program program = { compileShader(headerSource, vertexSource, GL_VERTEX_SHADER), compileShader(headerSource, fragmentSource, GL_FRAGMENT_SHADER), glCreateProgram(), }; if (!program.vertexShader || !program.fragmentShader || !program.program) { deleteProgram(program); return nullProgram; } glAttachShader(program.program, program.vertexShader); glAttachShader(program.program, program.fragmentShader); glLinkProgram(program.program); GLint status = 0; glGetProgramiv(program.program, GL_LINK_STATUS, &status); if (status == GL_FALSE) { GLint length = 0; glGetProgramiv(program.program, GL_INFO_LOG_LENGTH, &length); char* log = (char*)calloc(1, (size_t)length); glGetProgramInfoLog(program.program, length, &length, &log[0]); fprintf(stderr, "error: Failed to link program (%s)\n", log); free(log); deleteProgram(program); return nullProgram; } return program; } #endif // EXAMPLES_SHADER_UTILS_H