1/*
2Copyright (c) 2013, Broadcom Europe Ltd
3Copyright (c) 2013, Tim Gover
4All rights reserved.
5
6
7Redistribution and use in source and binary forms, with or without
8modification, are permitted provided that the following conditions are met:
9 * Redistributions of source code must retain the above copyright
10 notice, this list of conditions and the following disclaimer.
11 * Redistributions in binary form must reproduce the above copyright
12 notice, this list of conditions and the following disclaimer in the
13 documentation and/or other materials provided with the distribution.
14 * Neither the name of the copyright holder nor the
15 names of its contributors may be used to endorse or promote products
16 derived from this software without specific prior written permission.
17
18THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
19ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
20WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
21DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY
22DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
23(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
24LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
25ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
27SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28*/
29
30#include "mirror.h"
31#include "RaspiTex.h"
32#include "RaspiTexUtil.h"
33#include <GLES2/gl2.h>
34#include <EGL/egl.h>
35#include <EGL/eglext.h>
36
37/**
38 * Draws an external EGL image and applies a sine wave distortion to create
39 * a hall of mirrors effect.
40 */
41static RASPITEXUTIL_SHADER_PROGRAM_T mirror_shader = {
42 .vertex_source =
43 "attribute vec2 vertex;\n"
44 "varying vec2 texcoord;"
45 "void main(void) {\n"
46 " texcoord = 0.5 * (vertex + 1.0);\n"
47 " gl_Position = vec4(vertex, 0.0, 1.0);\n"
48 "}\n",
49
50 .fragment_source =
51 "#extension GL_OES_EGL_image_external : require\n"
52 "uniform samplerExternalOES tex;\n"
53 "uniform float offset;\n"
54 "const float waves = 2.0;\n"
55 "varying vec2 texcoord;\n"
56 "void main(void) {\n"
57 " float x = texcoord.x + 0.05 * sin(offset + (texcoord.y * waves * 2.0 * 3.141592));\n"
58 " float y = texcoord.y + 0.05 * sin(offset + (texcoord.x * waves * 2.0 * 3.141592));\n"
59 " if (y < 1.0 && y > 0.0 && x < 1.0 && x > 0.0) {\n"
60 " vec2 pos = vec2(x, y);\n"
61 " gl_FragColor = texture2D(tex, pos);\n"
62 " }\n"
63 " else {\n"
64 " gl_FragColor = vec4(0.0, 0.0, 0.0, 1.0);\n"
65 " }\n"
66 "}\n",
67 .uniform_names = {"tex", "offset"},
68 .attribute_names = {"vertex"},
69};
70
71/**
72 * Creates the OpenGL ES 2.X context and builds the shaders.
73 * @param raspitex_state A pointer to the GL preview state.
74 * @return Zero if successful.
75 */
76static int mirror_init(RASPITEX_STATE *state)
77{
78 int rc = raspitexutil_gl_init_2_0(state);
79 if (rc != 0)
80 goto end;
81
82 rc = raspitexutil_build_shader_program(&mirror_shader);
83end:
84 return rc;
85}
86
87static int mirror_redraw(RASPITEX_STATE *raspitex_state) {
88 static float offset = 0.0;
89
90 // Start with a clear screen
91 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
92
93 // Bind the OES texture which is used to render the camera preview
94 glBindTexture(GL_TEXTURE_EXTERNAL_OES, raspitex_state->texture);
95
96 offset += 0.05;
97 GLCHK(glUseProgram(mirror_shader.program));
98 GLCHK(glEnableVertexAttribArray(mirror_shader.attribute_locations[0]));
99 GLfloat varray[] = {
100 -1.0f, -1.0f,
101 1.0f, 1.0f,
102 1.0f, -1.0f,
103
104 -1.0f, 1.0f,
105 1.0f, 1.0f,
106 -1.0f, -1.0f,
107 };
108 GLCHK(glVertexAttribPointer(mirror_shader.attribute_locations[0], 2, GL_FLOAT, GL_FALSE, 0, varray));
109 GLCHK(glUniform1f(mirror_shader.uniform_locations[1], offset));
110 GLCHK(glDrawArrays(GL_TRIANGLES, 0, 6));
111
112 GLCHK(glDisableVertexAttribArray(mirror_shader.attribute_locations[0]));
113 GLCHK(glUseProgram(0));
114 return 0;
115}
116
117int mirror_open(RASPITEX_STATE *state)
118{
119 state->ops.gl_init = mirror_init;
120 state->ops.redraw = mirror_redraw;
121 state->ops.update_texture = raspitexutil_update_texture;
122 return 0;
123}
124