src/client/shader.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4 #include <unistd.h>
   5 #include "client/gl_debug.h"
   6 #include "client/shader.h"
   7
   8 static GLuint compile_shader(GLenum type, const char *path, const char *name, GLuint program, const char *definitions)
   9 {
  10         char full_path[strlen(path) + 1 + strlen(name) + 1 + 4 + 1];
  11         sprintf(full_path, "%s/%s.glsl", path, name);
  12
  13         FILE *file = fopen(full_path, "r");
  14         if (!file) {
  15                 perror("fopen");
  16                 return 0;
  17         }
  18
  19         if (fseek(file, 0, SEEK_END) == -1) {
  20                 perror("fseek");
  21                 fclose(file);
  22                 return 0;
  23         }
  24
  25         long size = ftell(file);
  26
  27         if (size == 1) {
  28                 perror("ftell");
  29                 fclose(file);
  30                 return 0;
  31         }
  32
  33         if (fseek(file, 0, SEEK_SET) == -1) {
  34                 perror("fseek");
  35                 fclose(file);
  36                 return 0;
  37         }
  38
  39         char code[size];
  40
  41         if (fread(code, 1, size, file) != (size_t) size) {
  42                 perror("fread");
  43                 fclose(file);
  44                 return 0;
  45         }
  46
  47         fclose(file);
  48
  49         GLuint id = glCreateShader(type); GL_DEBUG
  50
  51         // Minimum OpenGL version is 4.2.0 (idk some shader feature from that version is required)
  52         const char *version = "#version 420 core\n"; // 420 blaze it
  53
  54         const char *code_list[3] = {
  55                 version,
  56                 definitions,
  57                 code,
  58         };
  59
  60         int size_list[3] = {
  61                 18,
  62                 strlen(definitions),
  63                 size,
  64         };
  65
  66         glShaderSource(id, 3, code_list, size_list); GL_DEBUG
  67
  68         glCompileShader(id); GL_DEBUG
  69
  70         GLint success;
  71         glGetShaderiv(id, GL_COMPILE_STATUS, &success); GL_DEBUG
  72         if (!success) {
  73                 char errbuf[BUFSIZ];
  74                 glGetShaderInfoLog(id, BUFSIZ, NULL, errbuf); GL_DEBUG
  75                 fprintf(stderr, "[error] failed to compile %s shader: %s", name, errbuf);
  76                 glDeleteShader(id); GL_DEBUG
  77                 return 0;
  78         }
  79
  80         glAttachShader(program, id); GL_DEBUG
  81
  82         return id;
  83 }
  84
  85 bool shader_program_create(const char *path, GLuint *idptr, const char *definitions)
  86 {
  87         GLuint id = glCreateProgram(); GL_DEBUG
  88
  89         if (!definitions)
  90                 definitions = "";
  91
  92         GLuint vert, frag;
  93
  94         if (!(vert = compile_shader(GL_VERTEX_SHADER, path, "vertex", id, definitions))) {
  95                 glDeleteProgram(id); GL_DEBUG
  96                 return false;
  97         }
  98
  99         if (!(frag = compile_shader(GL_FRAGMENT_SHADER, path, "fragment", id, definitions))) {
 100                 glDeleteShader(vert); GL_DEBUG
 101                 glDeleteProgram(id); GL_DEBUG
 102                 return false;
 103         }
 104
 105         glLinkProgram(id); GL_DEBUG
 106         glDeleteShader(vert); GL_DEBUG
 107         glDeleteShader(frag); GL_DEBUG
 108
 109         GLint success;
 110         glGetProgramiv(id, GL_LINK_STATUS, &success); GL_DEBUG
 111         if (!success) {
 112                 char errbuf[BUFSIZ];
 113                 glGetProgramInfoLog(id, BUFSIZ, NULL, errbuf); GL_DEBUG
 114                 fprintf(stderr, "[error] failed to link shader program: %s\n", errbuf);
 115                 glDeleteProgram(id); GL_DEBUG
 116                 return false;
 117         }
 118
 119         *idptr = id;
 120         return true;
 121 }