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Moved OpenGLWidget into common folder so it can be used by other examples.

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This commit is contained in:
David Williams
2014-05-23 22:11:47 +02:00
parent 4f7e1e6846
commit d34fd6b3c8
4 changed files with 5 additions and 5 deletions
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194
examples/common/OpenGLWidget.cpp Normal file
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#include "OpenGLWidget.h"
#include <QMouseEvent>
#include <QMatrix4x4>
//#include <QtMath>
using namespace PolyVox;
using namespace std;
OpenGLWidget::OpenGLWidget(QWidget *parent)
:QGLWidget(parent)
,m_viewableRegion(Region(0, 0, 0, 255, 255, 255))
,m_xRotation(0)
,m_yRotation(0)
{
}
void OpenGLWidget::setViewableRegion(Region viewableRegion)
{
m_viewableRegion = viewableRegion;
setupWorldToCameraMatrix();
}
void OpenGLWidget::initializeGL()
{
GLenum err = glewInit();
if (GLEW_OK != err)
{
/* Problem: glewInit failed, something is seriously wrong. */
std::cout << "GLEW Error: " << glewGetErrorString(err) << std::endl;
}
//Print out some information about the OpenGL implementation.
std::cout << "OpenGL Implementation Details:" << std::endl;
if(glGetString(GL_VENDOR))
std::cout << "\tGL_VENDOR: " << glGetString(GL_VENDOR) << std::endl;
if(glGetString(GL_RENDERER))
std::cout << "\tGL_RENDERER: " << glGetString(GL_RENDERER) << std::endl;
if(glGetString(GL_VERSION))
std::cout << "\tGL_VERSION: " << glGetString(GL_VERSION) << std::endl;
if(glGetString(GL_SHADING_LANGUAGE_VERSION))
std::cout << "\tGL_SHADING_LANGUAGE_VERSION: " << glGetString(GL_SHADING_LANGUAGE_VERSION) << std::endl;
//Set up the clear colour
glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glClearDepth(1.0f);
glEnable(GL_CULL_FACE);
glEnable(GL_DEPTH_TEST);
glDepthMask(GL_TRUE);
glDepthFunc(GL_LEQUAL);
glDepthRange(0.0, 1.0);
if (!shader.addShaderFromSourceCode(QGLShader::Vertex, R"(
#version 140
in vec4 position; //This will be the position of the vertex in model-space
uniform mat4 cameraToClipMatrix;
uniform mat4 worldToCameraMatrix;
uniform mat4 modelToWorldMatrix;
out vec4 worldPosition; //This is being passed to the fragment shader to calculate the normals
void main()
{
worldPosition = modelToWorldMatrix * position;
vec4 cameraPosition = worldToCameraMatrix * worldPosition;
gl_Position = cameraToClipMatrix * cameraPosition;
}
)"))
{
std::cerr << shader.log().toStdString() << std::endl;
exit(EXIT_FAILURE);
}
if (!shader.addShaderFromSourceCode(QGLShader::Fragment, R"(
#version 130
in vec4 worldPosition; //Passed in from the vertex shader
out vec4 outputColor;
void main()
{
vec3 normal = normalize(cross(dFdy(worldPosition.xyz), dFdx(worldPosition.xyz)));
float color = clamp(abs(dot(normalize(normal.xyz), vec3(0.9,0.1,0.5))), 0, 1);
outputColor = vec4(1.0, 0.5, color, 1.0);
}
)"))
{
std::cerr << shader.log().toStdString() << std::endl;
exit(EXIT_FAILURE);
}
shader.bindAttributeLocation("position", 0);
if(!shader.link())
{
std::cerr << shader.log().toStdString() << std::endl;
exit(EXIT_FAILURE);
}
setupWorldToCameraMatrix();
}
void OpenGLWidget::resizeGL(int w, int h)
{
//Setup the viewport
glViewport(0, 0, w, h);
auto aspectRatio = w / (float)h;
float zNear = 1.0;
float zFar = 1000.0;
QMatrix4x4 cameraToClipMatrix{};
cameraToClipMatrix.frustum(-aspectRatio, aspectRatio, -1, 1, zNear, zFar);
shader.bind();
shader.setUniformValue("cameraToClipMatrix", cameraToClipMatrix);
shader.release();
}
void OpenGLWidget::paintGL()
{
//Clear the screen
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
shader.bind();
for (OpenGLMeshData meshData : mMeshData)
{
QMatrix4x4 modelToWorldMatrix{};
modelToWorldMatrix.translate(meshData.translation.getX(), meshData.translation.getY(), meshData.translation.getZ()); // Centre the model on the origin
shader.setUniformValue("modelToWorldMatrix", modelToWorldMatrix); // Update to the latest camera matrix
glBindVertexArray(meshData.vertexArrayObject);
glDrawElements(GL_TRIANGLES, meshData.noOfIndices, GL_UNSIGNED_INT, 0);
glBindVertexArray(0);
}
shader.release();
GLenum errCode = glGetError();
if(errCode != GL_NO_ERROR)
{
std::cerr << "OpenGL Error: " << errCode << std::endl;
}
}
void OpenGLWidget::mousePressEvent(QMouseEvent* event)
{
m_CurrentMousePos = event->pos();
m_LastFrameMousePos = m_CurrentMousePos;
update();
}
void OpenGLWidget::mouseMoveEvent(QMouseEvent* event)
{
m_CurrentMousePos = event->pos();
QPoint diff = m_CurrentMousePos - m_LastFrameMousePos;
m_xRotation += diff.x();
m_yRotation += diff.y();
m_LastFrameMousePos = m_CurrentMousePos;
setupWorldToCameraMatrix();
update();
}
void OpenGLWidget::setupWorldToCameraMatrix()
{
shader.bind();
QVector3D lowerCorner(m_viewableRegion.getLowerX(), m_viewableRegion.getLowerY(), m_viewableRegion.getLowerZ());
QVector3D upperCorner(m_viewableRegion.getUpperX(), m_viewableRegion.getUpperY(), m_viewableRegion.getUpperZ());
QVector3D centerPoint = (lowerCorner + upperCorner) * 0.5;
float fDiagonalLength = (upperCorner - lowerCorner).length();
QMatrix4x4 worldToCameraMatrix{};
worldToCameraMatrix.translate(0, 0, -fDiagonalLength / 2.0f); //Move the camera back by the required amount
worldToCameraMatrix.rotate(m_xRotation, 0, 1, 0); //rotate around y-axis
worldToCameraMatrix.rotate(m_yRotation, 1, 0, 0); //rotate around x-axis
worldToCameraMatrix.translate(-centerPoint); //centre the model on the origin
shader.setUniformValue("worldToCameraMatrix", worldToCameraMatrix);
shader.release();
}

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examples/common/OpenGLWidget.h Normal file
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/*******************************************************************************
Copyright (c) 2005-2009 David Williams
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source
distribution.
*******************************************************************************/
#ifndef __BasicExample_OpenGLWidget_H__
#define __BasicExample_OpenGLWidget_H__
#include "PolyVoxCore/Mesh.h"
#include "glew/glew.h"
#include <QGLWidget>
#include <QGLShaderProgram>
struct OpenGLMeshData
{
GLuint noOfIndices;
GLuint indexBuffer;
GLuint vertexBuffer;
GLuint vertexArrayObject;
PolyVox::Vector3DInt32 translation;
};
class OpenGLWidget : public QGLWidget
{
public:
// Constructor
OpenGLWidget(QWidget *parent);
// Mouse handling
void mouseMoveEvent(QMouseEvent* event);
void mousePressEvent(QMouseEvent* event);
// The viewable region can be adjusted so that this example framework can be use for different volume sizes.
void setViewableRegion(PolyVox::Region viewableRegion);
// Convert a SurfaceMesh to OpenGL index/vertex buffers. Inlined because it's templatised.
template <typename MeshType>
void addMesh(const MeshType& surfaceMesh)
{
//Convienient access to the vertices and indices
const auto& vecIndices = surfaceMesh.getIndices();
const auto& vecVertices = surfaceMesh.getVertices();
// This struct holds the OpenGL properties (buffer handles, etc) which will be used
// to render our mesh. We copy the data from the PolyVox mesh into this structure.
OpenGLMeshData meshData;
//Create the VAO for the mesh
glGenVertexArrays(1, &(meshData.vertexArrayObject));
glBindVertexArray(meshData.vertexArrayObject);
//The GL_ARRAY_BUFFER will contain the list of vertex positions
glGenBuffers(1, &(meshData.vertexBuffer));
glBindBuffer(GL_ARRAY_BUFFER, meshData.vertexBuffer);
glBufferData(GL_ARRAY_BUFFER, vecVertices.size() * sizeof(CubicVertex<uint8_t>), vecVertices.data(), GL_STATIC_DRAW);
//and GL_ELEMENT_ARRAY_BUFFER will contain the indices
glGenBuffers(1, &(meshData.indexBuffer));
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, meshData.indexBuffer);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, vecIndices.size() * sizeof(uint32_t), vecIndices.data(), GL_STATIC_DRAW);
//We need to tell OpenGL how to understand the format of the vertex data
glEnableVertexAttribArray(0); //We're talking about shader attribute '0'
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(CubicVertex<uint8_t>), 0); //take the first 3 floats from every sizeof(decltype(vecVertices)::value_type)
glBindVertexArray(0);
meshData.noOfIndices = vecIndices.size(); //Save this for the call to glDrawElements later
meshData.translation = surfaceMesh.m_Region.getLowerCorner();
mMeshData.push_back(meshData);
}
protected:
// Qt OpenGL functions
void initializeGL();
void resizeGL(int w, int h);
void paintGL();
private:
void setupWorldToCameraMatrix();
// Index/vertex buffer data
std::vector<OpenGLMeshData> mMeshData;
QGLShaderProgram shader;
// Mouse data
QPoint m_LastFrameMousePos;
QPoint m_CurrentMousePos;
// Camera setup
PolyVox::Region m_viewableRegion;
int m_xRotation;
int m_yRotation;
};
#endif //__BasicExample_OpenGLWidget_H__