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++ // Copyright (C) 2017 The Qt Company Ltd.
++ // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
++
++ #include "cuberenderer.h"
++ #include <QOpenGLContext>
++ #include <QOpenGLFunctions>
++ #include <QOpenGLShaderProgram>
++ #include <QOpenGLVertexArrayObject>
++ #include <QOpenGLBuffer>
++ #include <QOpenGLVertexArrayObject>
++ #include <QOffscreenSurface>
++ #include <QWindow>
++
++ CubeRenderer::CubeRenderer(QOffscreenSurface *offscreenSurface)
++ : m_offscreenSurface(offscreenSurface),
++ m_context(nullptr),
++ m_program(nullptr),
++ m_vbo(nullptr),
++ m_vao(nullptr),
++ m_matrixLoc(0)
++ {
++ }
++
++ CubeRenderer::~CubeRenderer()
++ {
++ // Use a temporary offscreen surface to do the cleanup.
++ // There may not be a native window surface available anymore at this stage.
++ m_context->makeCurrent(m_offscreenSurface);
++
++ delete m_program;
++ delete m_vbo;
++ delete m_vao;
++
++ m_context->doneCurrent();
++ delete m_context;
++ }
++
++ void CubeRenderer::init(QWindow *w, QOpenGLContext *share)
++ {
++ m_context = new QOpenGLContext;
++ m_context->setShareContext(share);
++ m_context->setFormat(w->requestedFormat());
++ m_context->create();
++ if (!m_context->makeCurrent(w))
++ return;
++
++ QOpenGLFunctions *f = m_context->functions();
++ f->glViewport(0, 0, w->width() * w->devicePixelRatio(), w->height() * w->devicePixelRatio());
++
++ static const char *vertexShaderSource =
++ "attribute highp vec4 vertex;\n"
++ "attribute lowp vec2 coord;\n"
++ "varying lowp vec2 v_coord;\n"
++ "uniform highp mat4 matrix;\n"
++ "void main() {\n"
++ " v_coord = coord;\n"
++ " gl_Position = matrix * vertex;\n"
++ "}\n";
++ static const char *fragmentShaderSource =
++ "varying lowp vec2 v_coord;\n"
++ "uniform sampler2D sampler;\n"
++ "void main() {\n"
++ " gl_FragColor = vec4(texture2D(sampler, v_coord).rgb, 1.0);\n"
++ "}\n";
++ m_program = new QOpenGLShaderProgram;
++ m_program->addCacheableShaderFromSourceCode(QOpenGLShader::Vertex, vertexShaderSource);
++ m_program->addCacheableShaderFromSourceCode(QOpenGLShader::Fragment, fragmentShaderSource);
++ m_program->bindAttributeLocation("vertex", 0);
++ m_program->bindAttributeLocation("coord", 1);
++ m_program->link();
++ m_matrixLoc = m_program->uniformLocation("matrix");
++
++ m_vao = new QOpenGLVertexArrayObject;
++ m_vao->create();
++ QOpenGLVertexArrayObject::Binder vaoBinder(m_vao);
++
++ m_vbo = new QOpenGLBuffer;
++ m_vbo->create();
++ m_vbo->bind();
++
++ GLfloat v[] = {
++ -0.5, 0.5, 0.5, 0.5,-0.5,0.5,-0.5,-0.5,0.5,
++ 0.5, -0.5, 0.5, -0.5,0.5,0.5,0.5,0.5,0.5,
++ -0.5, -0.5, -0.5, 0.5,-0.5,-0.5,-0.5,0.5,-0.5,
++ 0.5, 0.5, -0.5, -0.5,0.5,-0.5,0.5,-0.5,-0.5,
++
++ 0.5, -0.5, -0.5, 0.5,-0.5,0.5,0.5,0.5,-0.5,
++ 0.5, 0.5, 0.5, 0.5,0.5,-0.5,0.5,-0.5,0.5,
++ -0.5, 0.5, -0.5, -0.5,-0.5,0.5,-0.5,-0.5,-0.5,
++ -0.5, -0.5, 0.5, -0.5,0.5,-0.5,-0.5,0.5,0.5,
++
++ 0.5, 0.5, -0.5, -0.5, 0.5, 0.5, -0.5, 0.5, -0.5,
++ -0.5, 0.5, 0.5, 0.5, 0.5, -0.5, 0.5, 0.5, 0.5,
++ -0.5, -0.5, -0.5, -0.5, -0.5, 0.5, 0.5, -0.5, -0.5,
++ 0.5, -0.5, 0.5, 0.5, -0.5, -0.5, -0.5, -0.5, 0.5
++ };
++ GLfloat texCoords[] = {
++ 0.0f,0.0f, 1.0f,1.0f, 1.0f,0.0f,
++ 1.0f,1.0f, 0.0f,0.0f, 0.0f,1.0f,
++ 1.0f,1.0f, 1.0f,0.0f, 0.0f,1.0f,
++ 0.0f,0.0f, 0.0f,1.0f, 1.0f,0.0f,
++
++ 1.0f,1.0f, 1.0f,0.0f, 0.0f,1.0f,
++ 0.0f,0.0f, 0.0f,1.0f, 1.0f,0.0f,
++ 0.0f,0.0f, 1.0f,1.0f, 1.0f,0.0f,
++ 1.0f,1.0f, 0.0f,0.0f, 0.0f,1.0f,
++
++ 0.0f,1.0f, 1.0f,0.0f, 1.0f,1.0f,
++ 1.0f,0.0f, 0.0f,1.0f, 0.0f,0.0f,
++ 1.0f,0.0f, 1.0f,1.0f, 0.0f,0.0f,
++ 0.0f,1.0f, 0.0f,0.0f, 1.0f,1.0f
++ };
++
++ const int vertexCount = 36;
++ m_vbo->allocate(sizeof(GLfloat) * vertexCount * 5);
++ m_vbo->write(0, v, sizeof(GLfloat) * vertexCount * 3);
++ m_vbo->write(sizeof(GLfloat) * vertexCount * 3, texCoords, sizeof(GLfloat) * vertexCount * 2);
++ m_vbo->release();
++
++ if (m_vao->isCreated())
++ setupVertexAttribs();
++ }
++
++ void CubeRenderer::resize(int w, int h)
++ {
++ m_proj.setToIdentity();
++ m_proj.perspective(45, w / float(h), 0.01f, 100.0f);
++ }
++
++ void CubeRenderer::setupVertexAttribs()
++ {
++ m_vbo->bind();
++ m_program->enableAttributeArray(0);
++ m_program->enableAttributeArray(1);
++ m_context->functions()->glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, nullptr);
++ m_context->functions()->glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 0,
++ (const void *)(36 * 3 * sizeof(GLfloat)));
++ m_vbo->release();
++ }
++
++ void CubeRenderer::render(QWindow *w, QOpenGLContext *share, uint texture)
++ {
++ if (!m_context)
++ init(w, share);
++
++ if (!m_context->makeCurrent(w))
++ return;
++
++ QOpenGLFunctions *f = m_context->functions();
++ f->glClearColor(0.0f, 0.1f, 0.25f, 1.0f);
++ f->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
++
++ if (texture) {
++ f->glBindTexture(GL_TEXTURE_2D, texture);
++ f->glFrontFace(GL_CW); // because our cube's vertex data is such
++ f->glEnable(GL_CULL_FACE);
++ f->glEnable(GL_DEPTH_TEST);
++
++ m_program->bind();
++ QOpenGLVertexArrayObject::Binder vaoBinder(m_vao);
++ // If VAOs are not supported, set the vertex attributes every time.
++ if (!m_vao->isCreated())
++ setupVertexAttribs();
++
++ static GLfloat angle = 0;
++ QMatrix4x4 m;
++ m.translate(0, 0, -2);
++ m.rotate(90, 0, 0, 1);
++ m.rotate(angle, 0.5, 1, 0);
++ angle += 0.5f;
++
++ m_program->setUniformValue(m_matrixLoc, m_proj * m);
++
++ // Draw the cube.
++ f->glDrawArrays(GL_TRIANGLES, 0, 36);
++ }
++
++ m_context->swapBuffers(w);
++ }