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rtabmap/app/android/jni/background_renderer.cc

93 lines
2.7 KiB
C++

/*
* Copyright 2018 Google Inc. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
// This modules handles drawing the passthrough camera image into the OpenGL
// scene.
#include "background_renderer.h"
#include <type_traits>
namespace {
const std::string kVertexShader =
"attribute vec4 a_Position;\n"
"attribute vec2 a_TexCoord;\n"
"varying vec2 v_TexCoord;\n"
"void main() {\n"
" gl_Position = a_Position;\n"
" v_TexCoord = a_TexCoord;\n"
"}\n";
const std::string kFragmentShader =
"#extension GL_OES_EGL_image_external : require\n"
"precision mediump float;\n"
"varying vec2 v_TexCoord;\n"
"uniform samplerExternalOES sTexture;\n"
"void main() {\n"
" vec4 sample = texture2D(sTexture, v_TexCoord);\n"
" float grey = 0.21 * sample.r + 0.71 * sample.g + 0.07 * sample.b;\n"
" gl_FragColor = vec4(grey, grey, grey, 0.5);\n"
"}\n";
} // namespace
void BackgroundRenderer::InitializeGlContent(GLuint textureId)
{
texture_id_ = textureId;
shader_program_ = tango_gl::util::CreateProgram(kVertexShader.c_str(), kFragmentShader.c_str());
if (!shader_program_) {
LOGE("Could not create program.");
}
glUseProgram(shader_program_);
attribute_vertices_ = glGetAttribLocation(shader_program_, "a_Position");
attribute_uvs_ = glGetAttribLocation(shader_program_, "a_TexCoord");
glUseProgram(0);
}
void BackgroundRenderer::Draw(const float * transformed_uvs) {
static_assert(std::extent<decltype(BackgroundRenderer_kVertices)>::value == kNumVertices * 2, "Incorrect kVertices length");
glUseProgram(shader_program_);
glDepthMask(GL_FALSE);
glEnable (GL_BLEND);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_EXTERNAL_OES, texture_id_);
glVertexAttribPointer(attribute_vertices_, 2, GL_FLOAT, GL_FALSE, 0, BackgroundRenderer_kVertices);
glVertexAttribPointer(attribute_uvs_, 2, GL_FLOAT, GL_FALSE, 0, transformed_uvs);
glEnableVertexAttribArray(attribute_vertices_);
glEnableVertexAttribArray(attribute_uvs_);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
glDisableVertexAttribArray(attribute_vertices_);
glDisableVertexAttribArray(attribute_uvs_);
glUseProgram(0);
glDepthMask(GL_TRUE);
glDisable (GL_BLEND);
tango_gl::util::CheckGlError("BackgroundRenderer::Draw() error");
}