gl.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3
   4 #include <EGL/egl.h>
   5 #include <GLES/gl.h>
   6 #include "gl.h"
   7
   8 static EGLDisplay edpy;
   9 static EGLSurface esfc;
  10 static EGLContext ectxt;
  11
  12 static int gl_have_error(const char *name)
  13 {
  14         GLenum e = glGetError();
  15         if (e != GL_NO_ERROR) {
  16                 fprintf(stderr, "GL error: %s %x\n", name, e);
  17                 return 1;
  18         }
  19         return 0;
  20 }
  21
  22 static int gles_have_error(const char *name)
  23 {
  24         EGLint e = eglGetError();
  25         if (e != EGL_SUCCESS) {
  26                 fprintf(stderr, "%s %x\n", name, e);
  27                 return 1;
  28         }
  29         return 0;
  30 }
  31
  32 int gl_init(void *display, void *window)
  33 {
  34         EGLConfig ecfg = NULL;
  35         GLuint texture_name = 0;
  36         void *tmp_texture_mem = NULL;
  37         EGLint num_config;
  38         int retval = -1;
  39         int ret;
  40         EGLint attr[] =
  41         {
  42                 EGL_NONE
  43         };
  44
  45         tmp_texture_mem = calloc(1, 1024 * 512 * 2);
  46         if (tmp_texture_mem == NULL) {
  47                 fprintf(stderr, "OOM\n");
  48                 goto out;
  49         }
  50
  51         edpy = eglGetDisplay((EGLNativeDisplayType)display);
  52         if (edpy == EGL_NO_DISPLAY) {
  53                 fprintf(stderr, "Failed to get EGL display\n");
  54                 goto out;
  55         }
  56
  57         if (!eglInitialize(edpy, NULL, NULL)) {
  58                 fprintf(stderr, "Failed to initialize EGL\n");
  59                 goto out;
  60         }
  61
  62         if (!eglChooseConfig(edpy, attr, &ecfg, 1, &num_config)) {
  63                 fprintf(stderr, "Failed to choose config (%x)\n", eglGetError());
  64                 goto out;
  65         }
  66
  67         if (ecfg == NULL || num_config == 0) {
  68                 fprintf(stderr, "No EGL configs available\n");
  69                 goto out;
  70         }
  71
  72         esfc = eglCreateWindowSurface(edpy, ecfg,
  73                 (EGLNativeWindowType)window, NULL);
  74         if (esfc == EGL_NO_SURFACE) {
  75                 fprintf(stderr, "Unable to create EGL surface (%x)\n",
  76                         eglGetError());
  77                 goto out;
  78         }
  79
  80         ectxt = eglCreateContext(edpy, ecfg, EGL_NO_CONTEXT, NULL);
  81         if (ectxt == EGL_NO_CONTEXT) {
  82                 fprintf(stderr, "Unable to create EGL context (%x)\n",
  83                         eglGetError());
  84                 goto out;
  85         }
  86
  87         eglMakeCurrent(edpy, esfc, esfc, ectxt);
  88
  89         glEnable(GL_TEXTURE_2D);
  90
  91         glGenTextures(1, &texture_name);
  92
  93         glBindTexture(GL_TEXTURE_2D, texture_name);
  94
  95         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 1024, 512, 0, GL_RGB,
  96                 GL_UNSIGNED_SHORT_5_6_5, tmp_texture_mem);
  97         if (gl_have_error("glTexImage2D"))
  98                 goto out;
  99
 100         // no mipmaps
 101         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 102         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 103
 104         //glViewport(0, 0, 512, 512);
 105         glLoadIdentity();
 106         glFrontFace(GL_CW);
 107         glEnable(GL_CULL_FACE);
 108
 109         glEnableClientState(GL_TEXTURE_COORD_ARRAY);
 110         glEnableClientState(GL_VERTEX_ARRAY);
 111
 112         if (gl_have_error("init"))
 113                 goto out;
 114
 115         retval = 0;
 116 out:
 117         free(tmp_texture_mem);
 118         return retval;
 119 }
 120
 121 static float vertices[] = {
 122         -1.0f,  1.0f,  0.0f, // 0    0  1
 123          1.0f,  1.0f,  0.0f, // 1  ^
 124         -1.0f, -1.0f,  0.0f, // 2  | 2  3
 125          1.0f, -1.0f,  0.0f, // 3  +-->
 126 };
 127
 128 static float texture[] = {
 129         0.0f, 0.0f, // we flip this:
 130         1.0f, 0.0f, // v^
 131         0.0f, 1.0f, //  |  u
 132         1.0f, 1.0f, //  +-->
 133 };
 134
 135 int gl_flip(const void *fb, int w, int h)
 136 {
 137         static int old_w, old_h;
 138
 139         if (w != old_w || h != old_h) {
 140                 float f_w = (float)w / 1024.0f;
 141                 float f_h = (float)h / 512.0f;
 142                 texture[1*2 + 0] = f_w;
 143                 texture[2*2 + 1] = f_h;
 144                 texture[3*2 + 0] = f_w;
 145                 texture[3*2 + 1] = f_h;
 146                 old_w = w;
 147                 old_h = h;
 148         }
 149
 150         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, w, h,
 151                 GL_RGB, GL_UNSIGNED_SHORT_5_6_5, fb);
 152         if (gl_have_error("glTexSubImage2D"))
 153                 return -1;
 154
 155         glVertexPointer(3, GL_FLOAT, 0, vertices);
 156         glTexCoordPointer(2, GL_FLOAT, 0, texture);
 157         glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
 158
 159         if (gl_have_error("glDrawArrays"))
 160                 return -1;
 161
 162         eglSwapBuffers(edpy, esfc);
 163         if (gles_have_error("eglSwapBuffers"))
 164                 return -1;
 165
 166         return 0;
 167 }
 168
 169 void gl_finish(void)
 170 {
 171         eglMakeCurrent(edpy, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
 172         eglDestroyContext(edpy, ectxt);
 173         ectxt = EGL_NO_CONTEXT;
 174         eglDestroySurface(edpy, esfc);
 175         esfc = EGL_NO_SURFACE;
 176         eglTerminate(edpy);
 177         edpy = EGL_NO_DISPLAY;
 178 }