qemu

shader.c (5505B)

---

 /*
  * QEMU opengl shader helper functions
  *
  * Copyright (c) 2014 Red Hat
  *
  * Authors:
  *    Gerd Hoffmann <kraxel@redhat.com>
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */
 #include "qemu/osdep.h"
 #include "ui/shader.h"
 
 #include "ui/shader/texture-blit-vert.h"
 #include "ui/shader/texture-blit-flip-vert.h"
 #include "ui/shader/texture-blit-frag.h"
 
 struct QemuGLShader {
     GLint texture_blit_prog;
     GLint texture_blit_flip_prog;
     GLint texture_blit_vao;
 };
 
 /* ---------------------------------------------------------------------- */
 
 static GLuint qemu_gl_init_texture_blit(GLint texture_blit_prog)
 {
     static const GLfloat in_position[] = {
         -1, -1,
         1,  -1,
         -1,  1,
         1,   1,
     };
     GLint l_position;
     GLuint vao, buffer;
 
     glGenVertexArrays(1, &vao);
     glBindVertexArray(vao);
 
     /* this is the VBO that holds the vertex data */
     glGenBuffers(1, &buffer);
     glBindBuffer(GL_ARRAY_BUFFER, buffer);
     glBufferData(GL_ARRAY_BUFFER, sizeof(in_position), in_position,
                  GL_STATIC_DRAW);
 
     l_position = glGetAttribLocation(texture_blit_prog, "in_position");
     glVertexAttribPointer(l_position, 2, GL_FLOAT, GL_FALSE, 0, 0);
     glEnableVertexAttribArray(l_position);
 
     glBindBuffer(GL_ARRAY_BUFFER, 0);
     glBindVertexArray(0);
 
     return vao;
 }
 
 void qemu_gl_run_texture_blit(QemuGLShader *gls, bool flip)
 {
     glUseProgram(flip
                  ? gls->texture_blit_flip_prog
                  : gls->texture_blit_prog);
     glBindVertexArray(gls->texture_blit_vao);
     glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
 }
 
 /* ---------------------------------------------------------------------- */
 
 static GLuint qemu_gl_create_compile_shader(GLenum type, const GLchar *src)
 {
     GLuint shader;
     GLint status, length;
     char *errmsg;
 
     shader = glCreateShader(type);
     glShaderSource(shader, 1, &src, 0);
     glCompileShader(shader);
 
     glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
     if (!status) {
         glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &length);
         errmsg = g_malloc(length);
         glGetShaderInfoLog(shader, length, &length, errmsg);
         fprintf(stderr, "%s: compile %s error\n%s\n", __func__,
                 (type == GL_VERTEX_SHADER) ? "vertex" : "fragment",
                 errmsg);
         g_free(errmsg);
         return 0;
     }
     return shader;
 }
 
 static GLuint qemu_gl_create_link_program(GLuint vert, GLuint frag)
 {
     GLuint program;
     GLint status, length;
     char *errmsg;
 
     program = glCreateProgram();
     glAttachShader(program, vert);
     glAttachShader(program, frag);
     glLinkProgram(program);
 
     glGetProgramiv(program, GL_LINK_STATUS, &status);
     if (!status) {
         glGetProgramiv(program, GL_INFO_LOG_LENGTH, &length);
         errmsg = g_malloc(length);
         glGetProgramInfoLog(program, length, &length, errmsg);
         fprintf(stderr, "%s: link program: %s\n", __func__, errmsg);
         g_free(errmsg);
         return 0;
     }
     return program;
 }
 
 static GLuint qemu_gl_create_compile_link_program(const GLchar *vert_src,
                                                   const GLchar *frag_src)
 {
     GLuint vert_shader, frag_shader, program = 0;
 
     vert_shader = qemu_gl_create_compile_shader(GL_VERTEX_SHADER, vert_src);
     frag_shader = qemu_gl_create_compile_shader(GL_FRAGMENT_SHADER, frag_src);
     if (!vert_shader || !frag_shader) {
         goto end;
     }
 
     program = qemu_gl_create_link_program(vert_shader, frag_shader);
 
 end:
     glDeleteShader(vert_shader);
     glDeleteShader(frag_shader);
 
     return program;
 }
 
 /* ---------------------------------------------------------------------- */
 
 QemuGLShader *qemu_gl_init_shader(void)
 {
     QemuGLShader *gls = g_new0(QemuGLShader, 1);
 
     gls->texture_blit_prog = qemu_gl_create_compile_link_program
         (texture_blit_vert_src, texture_blit_frag_src);
     gls->texture_blit_flip_prog = qemu_gl_create_compile_link_program
         (texture_blit_flip_vert_src, texture_blit_frag_src);
     if (!gls->texture_blit_prog || !gls->texture_blit_flip_prog) {
         exit(1);
     }
 
     gls->texture_blit_vao =
         qemu_gl_init_texture_blit(gls->texture_blit_prog);
 
     return gls;
 }
 
 void qemu_gl_fini_shader(QemuGLShader *gls)
 {
     if (!gls) {
         return;
     }
     glDeleteProgram(gls->texture_blit_prog);
     glDeleteProgram(gls->texture_blit_flip_prog);
     glDeleteProgram(gls->texture_blit_vao);
     g_free(gls);
 }