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
34 struct QemuGLShader {
35 GLint texture_blit_prog;
36 GLint texture_blit_flip_prog;
37 GLint texture_blit_vao;
38 };
39
40 /* ---------------------------------------------------------------------- */
41
qemu_gl_init_texture_blit(GLint texture_blit_prog)42 static 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
qemu_gl_run_texture_blit(QemuGLShader * gls,bool flip)72 void 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
qemu_gl_create_compile_shader(GLenum type,const GLchar * src)83 static 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
qemu_gl_create_link_program(GLuint vert,GLuint frag)107 static 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
qemu_gl_create_compile_link_program(const GLchar * vert_src,const GLchar * frag_src)130 static 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
qemu_gl_init_shader(void)150 QemuGLShader *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
qemu_gl_fini_shader(QemuGLShader * gls)168 void qemu_gl_fini_shader(QemuGLShader *gls)
169 {
170 if (!gls) {
171 return;
172 }
173 g_free(gls);
174 }
175