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/*
* Copyright © 2012 Canonical Ltd.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Authored by: Alexandros Frantzis <alexandros.frantzis@canonical.com>
*/
#include "image_renderer.h"
// Unfortunately we have to ignore warnings/errors in 3rd party code.
#pragma GCC diagnostic push
#pragma GCC diagnostic warning "-Wall"
#include <glm/glm.hpp>
#pragma GCC diagnostic pop
#define GLM_FORCE_RADIANS
#include <glm/gtc/type_ptr.hpp>
#include <memory>
#include <vector>
#include <boost/throw_exception.hpp>
#include <stdexcept>
namespace mt = mir::tools;
namespace
{
const GLchar* vertex_shader_src =
{
"attribute vec3 position;\n"
"varying vec2 v_texcoord;\n"
"void main() {\n"
" gl_Position = vec4(position, 1.0);\n"
" v_texcoord = position.xy * 0.5 + 0.5;\n"
"}\n"
};
const GLchar* fragment_shader_src =
{
"#ifdef GL_ES\n"
"precision mediump float;\n"
"#endif\n"
"uniform sampler2D tex;\n"
"varying vec2 v_texcoord;\n"
"void main() {\n"
" gl_FragColor = texture2D(tex, v_texcoord);\n"
"}\n"
};
glm::vec3 vertex_attribs[4] =
{
glm::vec3{-1.0f, 1.0f, 0.0f},
glm::vec3{-1.0f, -1.0f, 0.0f},
glm::vec3{1.0f, 1.0f, 0.0f},
glm::vec3{1.0f, -1.0f, 0.0f}
};
typedef void(*MirGLGetObjectInfoLog)(GLuint, GLsizei, GLsizei *, GLchar *);
typedef void(*MirGLGetObjectiv)(GLuint, GLenum, GLint *);
void throw_with_object_log(MirGLGetObjectInfoLog getObjectInfoLog,
MirGLGetObjectiv getObjectiv,
std::string const & msg,
GLuint object)
{
GLint object_log_length = 0;
(*getObjectiv)(object, GL_INFO_LOG_LENGTH, &object_log_length);
GLuint const object_log_buffer_length = object_log_length + 1;
std::vector<char> log_chars(object_log_buffer_length);
(*getObjectInfoLog)(object, object_log_buffer_length, NULL, log_chars.data());
std::string object_info_err(msg + "\n");
object_info_err.append(log_chars.begin(), log_chars.end() - 1);
BOOST_THROW_EXCEPTION(std::runtime_error(object_info_err));
}
class GLState
{
public:
GLState(GLint attrib_loc)
: attrib_loc{attrib_loc}
{
glGetIntegerv(GL_CURRENT_PROGRAM, &program);
glGetIntegerv(GL_TEXTURE_BINDING_2D, &texture);
glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &buffer);
glGetIntegerv(GL_ACTIVE_TEXTURE, &active_texture_unit);
if (attrib_loc >= 0)
{
glGetVertexAttribiv(attrib_loc, GL_VERTEX_ATTRIB_ARRAY_ENABLED, &attrib_enabled);
glGetVertexAttribiv(attrib_loc, GL_VERTEX_ATTRIB_ARRAY_SIZE, &attrib_size);
glGetVertexAttribiv(attrib_loc, GL_VERTEX_ATTRIB_ARRAY_TYPE, &attrib_type);
glGetVertexAttribiv(attrib_loc, GL_VERTEX_ATTRIB_ARRAY_NORMALIZED, &attrib_normalized);
glGetVertexAttribiv(attrib_loc, GL_VERTEX_ATTRIB_ARRAY_STRIDE, &attrib_stride);
glGetVertexAttribPointerv(attrib_loc, GL_VERTEX_ATTRIB_ARRAY_POINTER, &attrib_pointer);
}
}
GLState() : GLState{invalid_attrib_loc} {}
~GLState()
{
glUseProgram(program);
glBindTexture(GL_TEXTURE_2D, texture);
glBindBuffer(GL_ARRAY_BUFFER, buffer);
glActiveTexture(active_texture_unit);
if (attrib_loc >= 0)
{
glVertexAttribPointer(attrib_loc, attrib_size, attrib_type,
attrib_normalized, attrib_stride, attrib_pointer);
if (attrib_enabled)
glEnableVertexAttribArray(attrib_loc);
else
glDisableVertexAttribArray(attrib_loc);
}
}
private:
static GLint const invalid_attrib_loc = -1;
GLint program = 0;
GLint texture = 0;
GLint buffer = 0;
GLint active_texture_unit = 0;
GLint attrib_loc = invalid_attrib_loc;
GLint attrib_enabled = 0;
GLint attrib_size = 0;
GLint attrib_type = 0;
GLint attrib_normalized = 0;
GLint attrib_stride = 0;
GLvoid* attrib_pointer = nullptr;
};
}
mt::ImageRenderer::ImageRenderer(const uint8_t* pixel_data, mir::geometry::Size size,
uint32_t bytes_per_pixel)
{
GLState gl_state;
resources.setup();
/* Upload the texture */
glBindTexture(GL_TEXTURE_2D, resources.texture);
GLenum format = (bytes_per_pixel == 3) ? GL_RGB : GL_RGBA;
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glTexImage2D(GL_TEXTURE_2D, 0, format,
size.width.as_uint32_t(), size.height.as_uint32_t(), 0,
format, GL_UNSIGNED_BYTE, pixel_data);
}
mt::ImageRenderer::Resources::~Resources()
{
if (vertex_shader)
glDeleteShader(vertex_shader);
if (fragment_shader)
glDeleteShader(fragment_shader);
if (program)
glDeleteProgram(program);
if (vertex_attribs_vbo)
glDeleteBuffers(1, &vertex_attribs_vbo);
if (texture)
glDeleteTextures(1, &texture);
}
void mt::ImageRenderer::Resources::setup()
{
GLint param = 0;
/* Create shaders and program */
vertex_shader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertex_shader, 1, &vertex_shader_src, 0);
glCompileShader(vertex_shader);
glGetShaderiv(vertex_shader, GL_COMPILE_STATUS, ¶m);
if (param == GL_FALSE)
{
throw_with_object_log(glGetShaderInfoLog, glGetShaderiv,
"Failed to compile vertex shader:",
vertex_shader);
}
fragment_shader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragment_shader, 1, &fragment_shader_src, 0);
glCompileShader(fragment_shader);
glGetShaderiv(fragment_shader, GL_COMPILE_STATUS, ¶m);
if (param == GL_FALSE)
{
throw_with_object_log(glGetShaderInfoLog, glGetShaderiv,
"Failed to compile fragment shader:",
fragment_shader);
}
program = glCreateProgram();
glAttachShader(program, vertex_shader);
glAttachShader(program, fragment_shader);
glLinkProgram(program);
glGetProgramiv(program, GL_LINK_STATUS, ¶m);
if (param == GL_FALSE)
{
throw_with_object_log(glGetProgramInfoLog, glGetProgramiv,
"Failed to link shader program:",
program);
}
glUseProgram(program);
/* Set up program variables */
GLint tex_loc = glGetUniformLocation(program, "tex");
position_attr_loc = glGetAttribLocation(program, "position");
/* Create the texture */
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glUniform1i(tex_loc, 0);
/* Create VBO */
glGenBuffers(1, &vertex_attribs_vbo);
glBindBuffer(GL_ARRAY_BUFFER, vertex_attribs_vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertex_attribs),
glm::value_ptr(vertex_attribs[0]), GL_STATIC_DRAW);
}
void mt::ImageRenderer::render()
{
GLState gl_state(resources.position_attr_loc);
glUseProgram(resources.program);
glActiveTexture(GL_TEXTURE0);
/* Set up vertex attribute data */
glBindBuffer(GL_ARRAY_BUFFER, resources.vertex_attribs_vbo);
glVertexAttribPointer(resources.position_attr_loc, 3, GL_FLOAT, GL_FALSE, 0, 0);
glBindTexture(GL_TEXTURE_2D, resources.texture);
/* Draw */
glEnableVertexAttribArray(resources.position_attr_loc);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
}
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