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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->glClearColor(0.0f, 0.1f, 0.25f, 1.0f);
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->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);
}
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