src/client/shader.c

   1 #include <string.h>
   2 #include <stdio.h>
   3 #include <unistd.h>
   4 #include <stdlib.h>
   5 #include "client/shader.h"
   6
   7 static GLuint compile_and_attach_shader(GLenum type, const char *path, const char *name, GLuint program, const char *definitions)
   8 {
   9         char full_path[strlen(path) + 1 + strlen(name) + 1 + 4 + 1];
  10         sprintf(full_path, "%s/%s.glsl", path, name);
  11
  12         FILE *file = fopen(full_path, "r");
  13         if (! file) {
  14                 perror("fopen");
  15                 return 0;
  16         }
  17
  18         if (fseek(file, 0, SEEK_END) == -1) {
  19                 perror("fseek");
  20                 fclose(file);
  21                 return 0;
  22         }
  23
  24         long size = ftell(file);
  25
  26         if (size == 1) {
  27                 perror("ftell");
  28                 fclose(file);
  29                 return 0;
  30         }
  31
  32         if (fseek(file, 0, SEEK_SET) == -1) {
  33                 perror("fseek");
  34                 fclose(file);
  35                 return 0;
  36         }
  37
  38         char code[size];
  39
  40         if (fread(code, 1, size, file) != (size_t) size) {
  41                 perror("fread");
  42                 fclose(file);
  43                 return 0;
  44         }
  45
  46         fclose(file);
  47
  48         GLuint id = glCreateShader(type);
  49
  50         const char *version = "#version 460 core\n";
  51
  52         const char *code_list[3] = {
  53                 version,
  54                 definitions,
  55                 code,
  56         };
  57
  58         int size_list[3] = {
  59                 18,
  60                 strlen(definitions),
  61                 size,
  62         };
  63
  64         glShaderSource(id, 3, code_list, size_list);
  65
  66         glCompileShader(id);
  67
  68         GLint success;
  69         glGetShaderiv(id, GL_COMPILE_STATUS, &success);
  70         if (! success) {
  71                 char errbuf[BUFSIZ];
  72                 glGetShaderInfoLog(id, BUFSIZ, NULL, errbuf);
  73                 fprintf(stderr, "Failed to compile %s shader: %s", name, errbuf);
  74                 glDeleteShader(id);
  75                 return 0;
  76         }
  77
  78         glAttachShader(program, id);
  79
  80         return id;
  81 }
  82
  83 bool shader_program_create(const char *path, GLuint *idptr, const char *definitions)
  84 {
  85         GLuint id = glCreateProgram();
  86
  87         if (! definitions)
  88                 definitions = "";
  89
  90         GLuint vert, frag;
  91
  92         if (! (vert = compile_and_attach_shader(GL_VERTEX_SHADER, path, "vertex", id, definitions))) {
  93                 glDeleteProgram(id);
  94                 return false;
  95         }
  96
  97         if (! (frag = compile_and_attach_shader(GL_FRAGMENT_SHADER, path, "fragment", id, definitions))) {
  98                 glDeleteShader(vert);
  99                 glDeleteProgram(id);
 100                 return false;
 101         }
 102
 103         glLinkProgram(id);
 104         glDeleteShader(vert);
 105         glDeleteShader(frag);
 106
 107         GLint success;
 108         glGetProgramiv(id, GL_LINK_STATUS, &success);
 109         if (! success) {
 110                 char errbuf[BUFSIZ];
 111                 glGetProgramInfoLog(id, BUFSIZ, NULL, errbuf);
 112                 fprintf(stderr, "Failed to link shader program: %s\n", errbuf);
 113                 glDeleteProgram(id);
 114                 return false;
 115         }
 116
 117         *idptr = id;
 118         return true;
 119 }