LXR qemu/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/osdep.h"
  28#include "ui/shader.h"
  29
  30#include "ui/shader/texture-blit-vert.h"
  31#include "ui/shader/texture-blit-flip-vert.h"
  32#include "ui/shader/texture-blit-frag.h"
  33
  34struct QemuGLShader {
  35    GLint texture_blit_prog;
  36    GLint texture_blit_flip_prog;
  37    GLint texture_blit_vao;
  38};
  39
  40/* ---------------------------------------------------------------------- */
  41
  42static GLuint qemu_gl_init_texture_blit(GLint texture_blit_prog)
  43{
  44    static const GLfloat in_position[] = {
  45        -1, -1,
  46        1,  -1,
  47        -1,  1,
  48        1,   1,
  49    };
  50    GLint l_position;
  51    GLuint vao, buffer;
  52
  53    glGenVertexArrays(1, &vao);
  54    glBindVertexArray(vao);
  55
  56    /* this is the VBO that holds the vertex data */
  57    glGenBuffers(1, &buffer);
  58    glBindBuffer(GL_ARRAY_BUFFER, buffer);
  59    glBufferData(GL_ARRAY_BUFFER, sizeof(in_position), in_position,
  60                 GL_STATIC_DRAW);
  61
  62    l_position = glGetAttribLocation(texture_blit_prog, "in_position");
  63    glVertexAttribPointer(l_position, 2, GL_FLOAT, GL_FALSE, 0, 0);
  64    glEnableVertexAttribArray(l_position);
  65
  66    glBindBuffer(GL_ARRAY_BUFFER, 0);
  67    glBindVertexArray(0);
  68
  69    return vao;
  70}
  71
  72void qemu_gl_run_texture_blit(QemuGLShader *gls, bool flip)
  73{
  74    glUseProgram(flip
  75                 ? gls->texture_blit_flip_prog
  76                 : gls->texture_blit_prog);
  77    glBindVertexArray(gls->texture_blit_vao);
  78    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
  79}
  80
  81/* ---------------------------------------------------------------------- */
  82
  83static GLuint qemu_gl_create_compile_shader(GLenum type, const GLchar *src)
  84{
  85    GLuint shader;
  86    GLint status, length;
  87    char *errmsg;
  88
  89    shader = glCreateShader(type);
  90    glShaderSource(shader, 1, &src, 0);
  91    glCompileShader(shader);
  92
  93    glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
  94    if (!status) {
  95        glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &length);
  96        errmsg = g_malloc(length);
  97        glGetShaderInfoLog(shader, length, &length, errmsg);
  98        fprintf(stderr, "%s: compile %s error\n%s\n", __func__,
  99                (type == GL_VERTEX_SHADER) ? "vertex" : "fragment",
 100                errmsg);
 101        g_free(errmsg);
 102        return 0;
 103    }
 104    return shader;
 105}
 106
 107static GLuint qemu_gl_create_link_program(GLuint vert, GLuint frag)
 108{
 109    GLuint program;
 110    GLint status, length;
 111    char *errmsg;
 112
 113    program = glCreateProgram();
 114    glAttachShader(program, vert);
 115    glAttachShader(program, frag);
 116    glLinkProgram(program);
 117
 118    glGetProgramiv(program, GL_LINK_STATUS, &status);
 119    if (!status) {
 120        glGetProgramiv(program, GL_INFO_LOG_LENGTH, &length);
 121        errmsg = g_malloc(length);
 122        glGetProgramInfoLog(program, length, &length, errmsg);
 123        fprintf(stderr, "%s: link program: %s\n", __func__, errmsg);
 124        g_free(errmsg);
 125        return 0;
 126    }
 127    return program;
 128}
 129
 130static GLuint qemu_gl_create_compile_link_program(const GLchar *vert_src,
 131                                                  const GLchar *frag_src)
 132{
 133    GLuint vert_shader, frag_shader, program;
 134
 135    vert_shader = qemu_gl_create_compile_shader(GL_VERTEX_SHADER, vert_src);
 136    frag_shader = qemu_gl_create_compile_shader(GL_FRAGMENT_SHADER, frag_src);
 137    if (!vert_shader || !frag_shader) {
 138        return 0;
 139    }
 140
 141    program = qemu_gl_create_link_program(vert_shader, frag_shader);
 142    glDeleteShader(vert_shader);
 143    glDeleteShader(frag_shader);
 144
 145    return program;
 146}
 147
 148/* ---------------------------------------------------------------------- */
 149
 150QemuGLShader *qemu_gl_init_shader(void)
 151{
 152    QemuGLShader *gls = g_new0(QemuGLShader, 1);
 153
 154    gls->texture_blit_prog = qemu_gl_create_compile_link_program
 155        (texture_blit_vert_src, texture_blit_frag_src);
 156    gls->texture_blit_flip_prog = qemu_gl_create_compile_link_program
 157        (texture_blit_flip_vert_src, texture_blit_frag_src);
 158    if (!gls->texture_blit_prog || !gls->texture_blit_flip_prog) {
 159        exit(1);
 160    }
 161
 162    gls->texture_blit_vao =
 163        qemu_gl_init_texture_blit(gls->texture_blit_prog);
 164
 165    return gls;
 166}
 167
 168void qemu_gl_fini_shader(QemuGLShader *gls)
 169{
 170    if (!gls) {
 171        return;
 172    }
 173    g_free(gls);
 174}
 175