| /* |
| * Copyright 2017 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 <type_traits> |
| |
| #include "platform_tools/android/apps/arcore/src/main/cpp/background_renderer.h" |
| |
| namespace hello_ar { |
| namespace { |
| // Positions of the quad vertices in clip space (X, Y, Z). |
| const GLfloat kVertices[] = { |
| -1.0f, -1.0f, 0.0f, +1.0f, -1.0f, 0.0f, |
| -1.0f, +1.0f, 0.0f, +1.0f, +1.0f, 0.0f, |
| }; |
| |
| // UVs of the quad vertices (S, T) |
| const GLfloat kUvs[] = { |
| 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, |
| }; |
| |
| constexpr char kVertexShader[] = R"( |
| attribute vec4 vertex; |
| attribute vec2 textureCoords; |
| varying vec2 v_textureCoords; |
| void main() { |
| v_textureCoords = textureCoords; |
| gl_Position = vertex; |
| })"; |
| |
| constexpr char kFragmentShader[] = R"( |
| #extension GL_OES_EGL_image_external : require |
| precision mediump float; |
| uniform samplerExternalOES texture; |
| varying vec2 v_textureCoords; |
| void main() { |
| gl_FragColor = texture2D(texture, v_textureCoords); |
| })"; |
| |
| } // namespace |
| |
| void BackgroundRenderer::InitializeGlContent() { |
| shader_program_ = util::CreateProgram(kVertexShader, kFragmentShader); |
| |
| if (!shader_program_) { |
| LOGE("Could not create program."); |
| } |
| |
| glGenTextures(1, &texture_id_); |
| glBindTexture(GL_TEXTURE_EXTERNAL_OES, texture_id_); |
| glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GL_TEXTURE_MIN_FILTER, GL_LINEAR); |
| glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GL_TEXTURE_MAG_FILTER, GL_LINEAR); |
| |
| uniform_texture_ = glGetUniformLocation(shader_program_, "texture"); |
| attribute_vertices_ = glGetAttribLocation(shader_program_, "vertex"); |
| attribute_uvs_ = glGetAttribLocation(shader_program_, "textureCoords"); |
| } |
| |
| void BackgroundRenderer::Draw(const ArSession *session, const ArFrame *frame) { |
| static_assert(std::extent<decltype(kUvs)>::value == kNumVertices * 2, |
| "Incorrect kUvs length"); |
| static_assert(std::extent<decltype(kVertices)>::value == kNumVertices * 3, |
| "Incorrect kVertices length"); |
| |
| // If display rotation changed (also includes view size change), we need to |
| // re-query the uv coordinates for the on-screen portion of the camera image. |
| int32_t geometry_changed = 0; |
| ArFrame_getDisplayGeometryChanged(session, frame, &geometry_changed); |
| if (geometry_changed != 0 || !uvs_initialized_) { |
| ArFrame_transformDisplayUvCoords(session, frame, kNumVertices * 2, kUvs, |
| transformed_uvs_); |
| uvs_initialized_ = true; |
| } |
| glUseProgram(shader_program_); |
| glDepthMask(GL_FALSE); |
| |
| glUniform1i(uniform_texture_, 1); |
| glActiveTexture(GL_TEXTURE1); |
| glBindTexture(GL_TEXTURE_EXTERNAL_OES, texture_id_); |
| |
| glEnableVertexAttribArray(attribute_vertices_); |
| glVertexAttribPointer(attribute_vertices_, 3, GL_FLOAT, GL_FALSE, 0, |
| kVertices); |
| |
| glEnableVertexAttribArray(attribute_uvs_); |
| glVertexAttribPointer(attribute_uvs_, 2, GL_FLOAT, GL_FALSE, 0, |
| transformed_uvs_); |
| |
| glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); |
| |
| glUseProgram(0); |
| glDepthMask(GL_TRUE); |
| util::CheckGlError("BackgroundRenderer::Draw() error"); |
| } |
| |
| GLuint BackgroundRenderer::GetTextureId() const { return texture_id_; } |
| |
| } // namespace hello_ar |