ui/shader.c

   1 /*
   2  * QEMU opengl shader helper functions
   3  *
   4  * Copyright (c) 2014 Red Hat
   5  *
   6  * Authors:
   7  *    Gerd Hoffmann <kraxel@redhat.com>
   8  *
   9  * Permission is hereby granted, free of charge, to any person obtaining a copy
  10  * of this software and associated documentation files (the "Software"), to deal
  11  * in the Software without restriction, including without limitation the rights
  12  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  13  * copies of the Software, and to permit persons to whom the Software is
  14  * furnished to do so, subject to the following conditions:
  15  *
  16  * The above copyright notice and this permission notice shall be included in
  17  * all copies or substantial portions of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  22  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  23  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  24  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  25  * THE SOFTWARE.
  26  */
  27 #include "qemu-common.h"
  28 #include "ui/shader.h"
  29
  30 /* ---------------------------------------------------------------------- */
  31
  32 void qemu_gl_run_texture_blit(GLint texture_blit_prog)
  33 {
  34     GLfloat in_position[] = {
  35         -1, -1,
  36         1,  -1,
  37         -1,  1,
  38         1,   1,
  39     };
  40     GLint l_position;
  41
  42     glUseProgram(texture_blit_prog);
  43     l_position = glGetAttribLocation(texture_blit_prog, "in_position");
  44     glVertexAttribPointer(l_position, 2, GL_FLOAT, GL_FALSE, 0, in_position);
  45     glEnableVertexAttribArray(l_position);
  46     glDrawArrays(GL_TRIANGLE_STRIP, l_position, 4);
  47 }
  48
  49 /* ---------------------------------------------------------------------- */
  50
  51 GLuint qemu_gl_create_compile_shader(GLenum type, const GLchar *src)
  52 {
  53     GLuint shader;
  54     GLint status, length;
  55     char *errmsg;
  56
  57     shader = glCreateShader(type);
  58     glShaderSource(shader, 1, &src, 0);
  59     glCompileShader(shader);
  60
  61     glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
  62     if (!status) {
  63         glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &length);
  64         errmsg = malloc(length);
  65         glGetShaderInfoLog(shader, length, &length, errmsg);
  66         fprintf(stderr, "%s: compile %s error\n%s\n", __func__,
  67                 (type == GL_VERTEX_SHADER) ? "vertex" : "fragment",
  68                 errmsg);
  69         free(errmsg);
  70         return 0;
  71     }
  72     return shader;
  73 }
  74
  75 GLuint qemu_gl_create_link_program(GLuint vert, GLuint frag)
  76 {
  77     GLuint program;
  78     GLint status, length;
  79     char *errmsg;
  80
  81     program = glCreateProgram();
  82     glAttachShader(program, vert);
  83     glAttachShader(program, frag);
  84     glLinkProgram(program);
  85
  86     glGetProgramiv(program, GL_LINK_STATUS, &status);
  87     if (!status) {
  88         glGetProgramiv(program, GL_INFO_LOG_LENGTH, &length);
  89         errmsg = malloc(length);
  90         glGetProgramInfoLog(program, length, &length, errmsg);
  91         fprintf(stderr, "%s: link program: %s\n", __func__, errmsg);
  92         free(errmsg);
  93         return 0;
  94     }
  95     return program;
  96 }
  97
  98 GLuint qemu_gl_create_compile_link_program(const GLchar *vert_src,
  99                                            const GLchar *frag_src)
 100 {
 101     GLuint vert_shader, frag_shader, program;
 102
 103     vert_shader = qemu_gl_create_compile_shader(GL_VERTEX_SHADER, vert_src);
 104     frag_shader = qemu_gl_create_compile_shader(GL_FRAGMENT_SHADER, frag_src);
 105     if (!vert_shader || !frag_shader) {
 106         return 0;
 107     }
 108
 109     program = qemu_gl_create_link_program(vert_shader, frag_shader);
 110     glDeleteShader(vert_shader);
 111     glDeleteShader(frag_shader);
 112
 113     return program;
 114 }