multiview

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Author : Stuart Morgan
Date : 2019-08-14 12:25:12
Hash : 9d737966
Message : Standardize copyright notices to project style For all "ANGLE Project" copyrights, standardize to the format specified by the style guide. Changes: - "Copyright (c)" and "Copyright(c)" changed to just "Copyright". - Removed the second half of date ranges ("Y1Y1-Y2Y2"->"Y1Y1"). - Fixed a small number of files that had no copyright date using the initial commit year from the version control history. - Fixed one instance of copyright being "The ANGLE Project" rather than "The ANGLE Project Authors" These changes are applied both to the copyright of source file, and where applicable to copyright statements that are generated by templates. BUG=angleproject:3811 Change-Id: I973dd65e4ef9deeba232d5be74c768256a0eb2e5 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1754397 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>
Multiview.cpp
//
// Copyright 2017 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// This sample shows basic usage of the GL_OVR_multiview2 extension.

#include "SampleApplication.h"

#include "util/geometry_utils.h"
#include "util/shader_utils.h"

#include <iostream>

namespace
{

void FillTranslationMatrix(float xOffset, float yOffset, float zOffset, float *matrix)
{
    matrix[0] = 1.0f;
    matrix[1] = 0.0f;
    matrix[2] = 0.0f;
    matrix[3] = xOffset;

    matrix[4] = 0.0f;
    matrix[5] = 1.0f;
    matrix[6] = 0.0f;
    matrix[7] = yOffset;

    matrix[8]  = 0.0f;
    matrix[9]  = 0.0f;
    matrix[10] = 1.0f;
    matrix[11] = zOffset;

    matrix[12] = 0.0f;
    matrix[13] = 0.0f;
    matrix[14] = 0.0f;
    matrix[15] = 1.0f;
}

}  // namespace

class MultiviewSample : public SampleApplication
{
  public:
    MultiviewSample(int argc, char **argv)
        : SampleApplication("Multiview", argc, argv, 3, 0),
          mMultiviewProgram(0),
          mMultiviewPersperiveUniformLoc(-1),
          mMultiviewLeftEyeCameraUniformLoc(-1),
          mMultiviewRightEyeCameraUniformLoc(-1),
          mMultiviewTranslationUniformLoc(-1),
          mMultiviewFBO(0),
          mColorTexture(0),
          mDepthTexture(0),
          mQuadVAO(0),
          mQuadVBO(0),
          mCubeVAO(0),
          mCubePosVBO(0),
          mCubeNormalVBO(0),
          mCubeIBO(0),
          mCombineProgram(0)
    {}

    bool initialize() override
    {
        // Check whether the GL_OVR_multiview(2) extension is supported. If not, abort
        // initialization.
        const char *allExtensions = reinterpret_cast<const char *>(glGetString(GL_EXTENSIONS));
        const std::string paddedExtensions = std::string(" ") + allExtensions + std::string(" ");
        if ((paddedExtensions.find(std::string(" GL_OVR_multiview2 ")) == std::string::npos) &&
            (paddedExtensions.find(std::string(" GL_OVR_multiview ")) == std::string::npos))
        {
            std::cout << "GL_OVR_multiview(2) is not available." << std::endl;
            return false;
        }

        // A view covers horizontally half of the screen.
        int viewWidth  = getWindow()->getWidth() / 2;
        int viewHeight = getWindow()->getHeight();

        // Create color and depth texture arrays with two layers to which we render each view.
        glGenTextures(1, &mColorTexture);
        glBindTexture(GL_TEXTURE_2D_ARRAY, mColorTexture);
        glTexImage3D(GL_TEXTURE_2D_ARRAY, 0, GL_RGBA8, viewWidth, viewHeight, 2, 0, GL_RGBA,
                     GL_UNSIGNED_BYTE, nullptr);
        glTexParameteri(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

        glGenTextures(1, &mDepthTexture);
        glBindTexture(GL_TEXTURE_2D_ARRAY, mDepthTexture);
        glTexImage3D(GL_TEXTURE_2D_ARRAY, 0, GL_DEPTH_COMPONENT32F, viewWidth, viewHeight, 2, 0,
                     GL_DEPTH_COMPONENT, GL_FLOAT, nullptr);

        // Generate multiview framebuffer for layered rendering.
        glGenFramebuffers(1, &mMultiviewFBO);
        glBindFramebuffer(GL_FRAMEBUFFER, mMultiviewFBO);
        glFramebufferTextureMultiviewOVR(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, mColorTexture, 0, 0,
                                         2);
        glFramebufferTextureMultiviewOVR(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, mDepthTexture, 0, 0,
                                         2);
        GLenum drawBuffer = GL_COLOR_ATTACHMENT0;
        glDrawBuffers(1, &drawBuffer);

        // Check that the framebuffer is complete. Abort initialization otherwise.
        if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
        {
            return false;
        }

        // Create multiview program and query the uniform locations.
        // The program has two code paths based on the gl_ViewID_OVR attribute which tells us which
        // view is currently being rendered to. Based on it we decide which eye's camera matrix to
        // use.
        constexpr char kMultiviewVS[] =
            "#version 300 es\n"
            "#extension GL_OVR_multiview2 : require\n"
            "layout(num_views = 2) in;\n"
            "layout(location=0) in vec3 posIn;\n"
            "layout(location=1) in vec3 normalIn;\n"
            "uniform mat4 uPerspective;\n"
            "uniform mat4 uCameraLeftEye;\n"
            "uniform mat4 uCameraRightEye;\n"
            "uniform mat4 uTranslation;\n"
            "out vec3 oNormal;\n"
            "void main()\n"
            "{\n"
            "   vec4 p = uTranslation * vec4(posIn,1.);\n"
            "   if (gl_ViewID_OVR == 0u) {\n"
            "       p = uCameraLeftEye * p;\n"
            "   } else {\n"
            "       p = uCameraRightEye * p;\n"
            "   }\n"
            "   oNormal = normalIn;\n"
            "   gl_Position = uPerspective * p;\n"
            "}\n";

        constexpr char kMultiviewFS[] =
            "#version 300 es\n"
            "#extension GL_OVR_multiview2 : require\n"
            "precision mediump float;\n"
            "out vec4 color;\n"
            "in vec3 oNormal;\n"
            "void main()\n"
            "{\n"
            "   vec3 col = 0.5 * oNormal + vec3(0.5);\n"
            "   color = vec4(col, 1.);\n"
            "}\n";

        mMultiviewProgram = CompileProgram(kMultiviewVS, kMultiviewFS);
        if (!mMultiviewProgram)
        {
            return false;
        }
        mMultiviewPersperiveUniformLoc = glGetUniformLocation(mMultiviewProgram, "uPerspective");
        mMultiviewLeftEyeCameraUniformLoc =
            glGetUniformLocation(mMultiviewProgram, "uCameraLeftEye");
        mMultiviewRightEyeCameraUniformLoc =
            glGetUniformLocation(mMultiviewProgram, "uCameraRightEye");
        mMultiviewTranslationUniformLoc = glGetUniformLocation(mMultiviewProgram, "uTranslation");

        // Create a normal program to combine both layers of the color array texture.
        constexpr char kCombineVS[] =
            "#version 300 es\n"
            "in vec2 vIn;\n"
            "out vec2 uv;\n"
            "void main()\n"
            "{\n"
            "   gl_Position = vec4(vIn, 0., 1.);\n"
            "   uv = vIn * .5 + vec2(.5);\n"
            "}\n";

        constexpr char kCombineFS[] =
            "#version 300 es\n"
            "precision mediump float;\n"
            "precision mediump sampler2DArray;\n"
            "uniform sampler2DArray uMultiviewTex;\n"
            "in vec2 uv;\n"
            "out vec4 color;\n"
            "void main()\n"
            "{\n"
            "   float scaledX = 2.0 * uv.x;\n"
            "   float layer = floor(scaledX);\n"
            "   vec2 adjustedUV = vec2(fract(scaledX), uv.y);\n"
            "   vec3 texColor = texture(uMultiviewTex, vec3(adjustedUV, layer)).rgb;\n"
            "   color = vec4(texColor, 1.);\n"
            "}\n";

        mCombineProgram = CompileProgram(kCombineVS, kCombineFS);
        if (!mCombineProgram)
        {
            return false;
        }

        // Generate a quad which covers the whole screen.
        glGenVertexArrays(1, &mQuadVAO);
        glBindVertexArray(mQuadVAO);

        glGenBuffers(1, &mQuadVBO);
        glBindBuffer(GL_ARRAY_BUFFER, mQuadVBO);
        const float kQuadPositionData[] = {1.f, -1.f, 1.f, 1.f, -1.f, -1.f, -1.f, 1.f};
        glBufferData(GL_ARRAY_BUFFER, sizeof(float) * 8, kQuadPositionData, GL_STATIC_DRAW);
        glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, nullptr);
        glEnableVertexAttribArray(0);
        glBindVertexArray(0);

        // Generate a cube.
        GenerateCubeGeometry(1.0f, &mCube);
        glGenVertexArrays(1, &mCubeVAO);
        glBindVertexArray(mCubeVAO);

        glGenBuffers(1, &mCubePosVBO);
        glBindBuffer(GL_ARRAY_BUFFER, mCubePosVBO);
        glBufferData(GL_ARRAY_BUFFER, sizeof(angle::Vector3) * mCube.positions.size(),
                     mCube.positions.data(), GL_STATIC_DRAW);
        glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, nullptr);
        glEnableVertexAttribArray(0);

        glGenBuffers(1, &mCubeNormalVBO);
        glBindBuffer(GL_ARRAY_BUFFER, mCubeNormalVBO);
        glBufferData(GL_ARRAY_BUFFER, sizeof(angle::Vector3) * mCube.normals.size(),
                     mCube.normals.data(), GL_STATIC_DRAW);
        glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 0, nullptr);
        glEnableVertexAttribArray(1);

        glGenBuffers(1, &mCubeIBO);
        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mCubeIBO);
        glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(GLushort) * mCube.indices.size(),
                     mCube.indices.data(), GL_STATIC_DRAW);

        glBindVertexArray(0);

        glEnable(GL_DEPTH_TEST);
        glClearColor(0.0f, 0.0f, 0.0f, 0.0f);

        return true;
    }

    void destroy() override
    {
        glDeleteProgram(mMultiviewProgram);
        glDeleteFramebuffers(1, &mMultiviewFBO);
        glDeleteTextures(1, &mColorTexture);
        glDeleteTextures(1, &mDepthTexture);
        glDeleteVertexArrays(1, &mQuadVAO);
        glDeleteBuffers(1, &mQuadVBO);
        glDeleteVertexArrays(1, &mCubeVAO);
        glDeleteBuffers(1, &mQuadVBO);
        glDeleteBuffers(1, &mCubePosVBO);
        glDeleteBuffers(1, &mCubeNormalVBO);
        glDeleteBuffers(1, &mCubeIBO);
        glDeleteProgram(mCombineProgram);
    }

    void draw() override
    {
        // Draw to multiview fbo.
        {
            // Generate the perspective projection matrix.
            const int viewWidth          = getWindow()->getWidth() / 2;
            const int viewHeight         = getWindow()->getHeight();
            const float kFOV             = 90.f;
            const float kNear            = 1.0f;
            const float kFar             = 100.0f;
            const float kPlaneDifference = kFar - kNear;
            const float kXYScale         = 1.f / (tanf(kFOV / 2.0f));
            const float kAspectRatio     = static_cast<float>(viewWidth) / viewHeight;
            float kPerspectiveProjectionMatrix[16];
            kPerspectiveProjectionMatrix[0] = kXYScale / kAspectRatio;
            kPerspectiveProjectionMatrix[1] = .0f;
            kPerspectiveProjectionMatrix[2] = .0f;
            kPerspectiveProjectionMatrix[3] = .0f;

            kPerspectiveProjectionMatrix[4] = .0f;
            kPerspectiveProjectionMatrix[5] = kXYScale;
            kPerspectiveProjectionMatrix[6] = .0f;
            kPerspectiveProjectionMatrix[7] = .0f;

            kPerspectiveProjectionMatrix[8]  = .0f;
            kPerspectiveProjectionMatrix[9]  = .0;
            kPerspectiveProjectionMatrix[10] = -kFar / kPlaneDifference;
            kPerspectiveProjectionMatrix[11] = -1.f;

            kPerspectiveProjectionMatrix[12] = .0f;
            kPerspectiveProjectionMatrix[13] = .0;
            kPerspectiveProjectionMatrix[14] = -kFar * kNear / kPlaneDifference;
            kPerspectiveProjectionMatrix[15] = .0;

            // Generate the camera matrices for the left and right eye.
            const float kXOffset = 1.5f;
            const float kYOffset = 1.5f;
            const float kZOffset = 5.0f;
            float kLeftCameraMatrix[16];
            FillTranslationMatrix(kXOffset, -kYOffset, -kZOffset, kLeftCameraMatrix);
            float kRightCameraMatrix[16];
            FillTranslationMatrix(-kXOffset, -kYOffset, -kZOffset, kRightCameraMatrix);

            // Bind and clear the multiview framebuffer.
            glBindFramebuffer(GL_FRAMEBUFFER, mMultiviewFBO);
            glClearColor(0, 0, 0, 1);
            glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

            // Set the viewport to be the size as one of the views.
            glViewport(0, 0, viewWidth, viewHeight);

            // Bind multiview program and set matrices.
            glUseProgram(mMultiviewProgram);
            glUniformMatrix4fv(mMultiviewPersperiveUniformLoc, 1, GL_TRUE,
                               kPerspectiveProjectionMatrix);
            glUniformMatrix4fv(mMultiviewLeftEyeCameraUniformLoc, 1, GL_TRUE, kLeftCameraMatrix);
            glUniformMatrix4fv(mMultiviewRightEyeCameraUniformLoc, 1, GL_TRUE, kRightCameraMatrix);

            glBindVertexArray(mCubeVAO);

            // Draw first cube.
            float kTranslationMatrix[16];
            FillTranslationMatrix(0.0f, 0.0f, 0.0f, kTranslationMatrix);
            glUniformMatrix4fv(mMultiviewTranslationUniformLoc, 1, GL_TRUE, kTranslationMatrix);
            glDrawElements(GL_TRIANGLES, static_cast<GLsizei>(mCube.indices.size()),
                           GL_UNSIGNED_SHORT, nullptr);

            // Draw second cube.
            FillTranslationMatrix(1.0f, 1.0f, -2.0f, kTranslationMatrix);
            glUniformMatrix4fv(mMultiviewTranslationUniformLoc, 1, GL_TRUE, kTranslationMatrix);
            glDrawElements(GL_TRIANGLES, static_cast<GLsizei>(mCube.indices.size()),
                           GL_UNSIGNED_SHORT, nullptr);

            glBindVertexArray(0);
        }

        // Combine both views.
        {
            // Bind the default framebuffer object and clear.
            glBindFramebuffer(GL_FRAMEBUFFER, 0);

            glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

            // Set the viewport to cover the whole screen.
            glViewport(0, 0, getWindow()->getWidth(), getWindow()->getHeight());

            glUseProgram(mCombineProgram);

            // Bind the 2D array texture to be used as a sampler.
            glUniform1i(glGetUniformLocation(mCombineProgram, "uMultiviewTex"), 0);
            glBindTexture(GL_TEXTURE_2D_ARRAY, mMultiviewFBO);
            glActiveTexture(GL_TEXTURE0);

            // Draw a quad which covers the whole screen. Layer and texture coordinates are
            // calculated in the vertex shader based on the UV coordinates of the quad.
            glBindVertexArray(mQuadVAO);
            glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
            glBindVertexArray(0);
        }
    }

  private:
    GLuint mMultiviewProgram;
    GLint mMultiviewPersperiveUniformLoc;
    GLint mMultiviewLeftEyeCameraUniformLoc;
    GLint mMultiviewRightEyeCameraUniformLoc;
    GLint mMultiviewTranslationUniformLoc;

    GLuint mMultiviewFBO;
    GLuint mColorTexture;
    GLuint mDepthTexture;

    GLuint mQuadVAO;
    GLuint mQuadVBO;

    CubeGeometry mCube;
    GLuint mCubeVAO;
    GLuint mCubePosVBO;
    GLuint mCubeNormalVBO;
    GLuint mCubeIBO;

    GLuint mCombineProgram;
};

int main(int argc, char **argv)
{
    MultiviewSample app(argc, argv);
    return app.run();
}
kc3-lang/angle/samples/multiview

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kc3-lang/angle /samples/multiview
