plzpart-gl/opengl.c

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <stdlib.h>
   4 #include <math.h>
   5 #include <GLES2/gl2.h>
   6 #include "u2gl.h"
   7 #include "opengl.h"
   8
   9 static int view_width;
  10 static int view_height;
  11
  12 static struct u2gl_program bg_program;
  13
  14 float obj[9];
  15
  16 float bg_obj[12] = {
  17         0.0f, 0.0f, 0.0f,
  18         320.0f, 0.0f, 0.0f,
  19         0.0f, 200.0f, 0.0f,
  20         320.0f, 200.0f, 0.0f
  21 };
  22
  23 static const char vertex_shader_texture[] =
  24 "uniform mat4 pMatrix;\n"
  25 "uniform mat4 uMatrix;\n"
  26 "attribute vec4 aPosition;\n"
  27 "varying vec3 vPosition;\n"
  28 "attribute vec2 aTexPosition;\n"
  29 "varying vec2 vTexPosition;\n"
  30 "\n"
  31 "void main() {\n"
  32 "    mat4 Matrix = pMatrix * uMatrix;\n"
  33 "    vec4 position = Matrix * aPosition;\n"
  34 "    gl_Position = position;\n"
  35 "    vTexPosition = aTexPosition;\n"
  36 "    vPosition = vec3(position);\n"
  37 "}\n";
  38
  39 static char fragment_shader_texture[20000];
  40
  41 int uRes_location;
  42 int uTime_location;
  43
  44 static float tex_coords[] = {
  45         0.0f, 1.0f,
  46         1.0f, 1.0f,
  47         0.0f, 0.0f,
  48         1.0f, 0.0f
  49 };
  50
  51 void draw_bg(float t)
  52 {
  53         glUniform1f(uTime_location, t);
  54
  55         //glActiveTexture(GL_TEXTURE0);
  56         //glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 320, 400, GL_RGB,
  57         //                              GL_UNSIGNED_BYTE, image);
  58         glUseProgram(bg_program.program);
  59         u2gl_draw_textured_triangle_strip(&bg_program, bg_obj, 4);
  60 }
  61
  62 #if 0
  63 static void init_texture()
  64 {
  65         GLuint tex[3];
  66
  67         u2gl_set_tex_coords(tex_coords);
  68
  69         glGenTextures(1, tex);
  70         glActiveTexture(GL_TEXTURE0);
  71         glBindTexture(GL_TEXTURE_2D, tex[0]);
  72         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
  73         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
  74         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  75         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  76
  77         image = calloc(3, 320 * 400);
  78
  79         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 320, 400, 0, GL_RGB,
  80                                 GL_UNSIGNED_BYTE, image);
  81         glGenerateMipmap(GL_TEXTURE_2D);
  82         u2gl_check_error("init_texture 1");
  83 }
  84 #endif
  85
  86 extern int window_width;
  87 extern int window_height;
  88
  89 int init_opengl()
  90 {
  91         GLuint v, f;
  92         FILE *in;
  93
  94         view_width = 320;
  95         view_height = 200;
  96
  97         in = fopen("plz.glsl", "r");
  98         if (in != NULL) {
  99                 fread(fragment_shader_texture, 20000, 1, in);
 100                 fclose(in);
 101         }
 102
 103         v = u2gl_compile_vertex_shader(vertex_shader_texture);
 104         f = u2gl_compile_fragment_shader(fragment_shader_texture);
 105         u2gl_create_program(&bg_program, f, v);
 106         u2gl_check_error("create program bg");
 107
 108         uRes_location = glGetUniformLocation(bg_program.program, "iResolution");
 109         uTime_location = glGetUniformLocation(bg_program.program, "iGlobalTime");
 110         u2gl_check_error("get uniform locations");
 111
 112         glUniform3f(uRes_location, (float)window_width, (float)window_height, 0.0f);
 113         u2gl_check_error("set resolution");
 114
 115         glDisable(GL_DEPTH_TEST);
 116         glEnable(GL_BLEND);
 117
 118         //glBlendFunc(GL_SRC_ALPHA, GL_ONE);
 119         glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 120
 121         glClearColor(.0, .0, .0, 0);
 122         u2gl_check_error("init_opengl");
 123
 124         //init_texture();
 125         //u2gl_check_error("init_texture");
 126
 127         u2gl_projection(0, view_width, 0, view_height, &bg_program);
 128
 129         return 0;
 130 }
 131
 132 void clear_screen()
 133 {
 134         glClear(GL_COLOR_BUFFER_BIT);
 135 }