SWBF2-Classic-Msh-Viewer/QtMeshViewer/Source/GeometryEngine.cpp

155 lines
5.0 KiB
C++

#include "..\Header\GeometryEngine.h"
#include <QVector2D>
#include <QVector3D>
struct VertexData
{
QVector3D position;
QVector2D texCoord;
};
GeometryEngine::GeometryEngine()
: indexBuf(QOpenGLBuffer::IndexBuffer)
, texture(Q_NULLPTR)
{
initializeOpenGLFunctions();
// Generate 2 VBOs
arrayBuf.create();
indexBuf.create();
// Initializes cube geometry and transfers it to VBOs
initCubeGeometry();
}
GeometryEngine::~GeometryEngine()
{
arrayBuf.destroy();
indexBuf.destroy();
delete texture;
}
void GeometryEngine::initCubeGeometry()
{
// For cube we would need only 8 vertices but we have to
// duplicate vertex for each face because texture coordinate
// is different.
VertexData vertices[] = {
// Vertex data for face 0
{QVector3D(-1.0f, -1.0f, 1.0f), QVector2D(0.0f, 0.0f)}, // v0
{QVector3D( 1.0f, -1.0f, 1.0f), QVector2D(0.33f, 0.0f)}, // v1
{QVector3D(-1.0f, 1.0f, 1.0f), QVector2D(0.0f, 0.5f)}, // v2
{QVector3D( 1.0f, 1.0f, 1.0f), QVector2D(0.33f, 0.5f)}, // v3
// Vertex data for face 1
{QVector3D( 1.0f, -1.0f, 1.0f), QVector2D( 0.0f, 0.5f)}, // v4
{QVector3D( 1.0f, -1.0f, -1.0f), QVector2D(0.33f, 0.5f)}, // v5
{QVector3D( 1.0f, 1.0f, 1.0f), QVector2D(0.0f, 1.0f)}, // v6
{QVector3D( 1.0f, 1.0f, -1.0f), QVector2D(0.33f, 1.0f)}, // v7
// Vertex data for face 2
{QVector3D( 1.0f, -1.0f, -1.0f), QVector2D(0.66f, 0.5f)}, // v8
{QVector3D(-1.0f, -1.0f, -1.0f), QVector2D(1.0f, 0.5f)}, // v9
{QVector3D( 1.0f, 1.0f, -1.0f), QVector2D(0.66f, 1.0f)}, // v10
{QVector3D(-1.0f, 1.0f, -1.0f), QVector2D(1.0f, 1.0f)}, // v11
// Vertex data for face 3
{QVector3D(-1.0f, -1.0f, -1.0f), QVector2D(0.66f, 0.0f)}, // v12
{QVector3D(-1.0f, -1.0f, 1.0f), QVector2D(1.0f, 0.0f)}, // v13
{QVector3D(-1.0f, 1.0f, -1.0f), QVector2D(0.66f, 0.5f)}, // v14
{QVector3D(-1.0f, 1.0f, 1.0f), QVector2D(1.0f, 0.5f)}, // v15
// Vertex data for face 4
{QVector3D(-1.0f, -1.0f, -1.0f), QVector2D(0.33f, 0.0f)}, // v16
{QVector3D( 1.0f, -1.0f, -1.0f), QVector2D(0.66f, 0.0f)}, // v17
{QVector3D(-1.0f, -1.0f, 1.0f), QVector2D(0.33f, 0.5f)}, // v18
{QVector3D( 1.0f, -1.0f, 1.0f), QVector2D(0.66f, 0.5f)}, // v19
// Vertex data for face 5
{QVector3D(-1.0f, 1.0f, 1.0f), QVector2D(0.33f, 0.5f)}, // v20
{QVector3D( 1.0f, 1.0f, 1.0f), QVector2D(0.66f, 0.5f)}, // v21
{QVector3D(-1.0f, 1.0f, -1.0f), QVector2D(0.33f, 1.0f)}, // v22
{QVector3D( 1.0f, 1.0f, -1.0f), QVector2D(0.66f, 1.0f)} // v23
};
// Indices for drawing cube faces using triangle strips.
// Triangle strips can be connected by duplicating indices
// between the strips. If connecting strips have opposite
// vertex order then last index of the first strip and first
// index of the second strip needs to be duplicated. If
// connecting strips have same vertex order then only last
// index of the first strip needs to be duplicated.
GLushort indices[] = {
0,1,2, //vorne (4)
3,2,1,
4,5,7, //rechts (1)
6,4,7,
8,9,11, //hinten (3)*
8,11,10,
14,12,13, //links (6)*
14,13,15,
18,16,17, //unten (5)
19,18,17,
23,22,20, //oben (2)*
23,20,21
};
// Transfer vertex data to VBO 0
arrayBuf.bind();
arrayBuf.allocate(vertices, 24 * sizeof(VertexData));
// Transfer index data to VBO 1
indexBuf.bind();
indexBuf.allocate(indices, 36 * sizeof(GLushort));
initTexture();
}
void GeometryEngine::initTexture()
{
// Load cube.png image
texture = new QOpenGLTexture(QImage(":images/cube.png").mirrored());
// Set nearest filtering mode for texture minification
texture->setMinificationFilter(QOpenGLTexture::Nearest);
// Set bilinear filtering mode for texture magnification
texture->setMagnificationFilter(QOpenGLTexture::Linear);
// Wrap texture coordinates by repeating
// f.ex. texture coordinate (1.1, 1.2) is same as (0.1, 0.2)
texture->setWrapMode(QOpenGLTexture::Repeat);
}
void GeometryEngine::drawGeometry(QOpenGLShaderProgram *program)
{
// Tell OpenGL which VBOs to use
arrayBuf.bind();
indexBuf.bind();
texture->bind();
// Use texture unit 0 which contains cube.png
program->setUniformValue("texture", 0);
// Offset for position
quintptr offset = 0;
// Tell OpenGL programmable pipeline how to locate vertex position data
int vertexLocation = program->attributeLocation("a_position");
program->enableAttributeArray(vertexLocation);
program->setAttributeBuffer(vertexLocation, GL_FLOAT, offset, 3, sizeof(VertexData));
// Offset for texture coordinate
offset += sizeof(QVector3D);
// Tell OpenGL programmable pipeline how to locate vertex texture coordinate data
int texcoordLocation = program->attributeLocation("a_texcoord");
program->enableAttributeArray(texcoordLocation);
program->setAttributeBuffer(texcoordLocation, GL_FLOAT, offset, 2, sizeof(VertexData));
// Draw cube geometry using indices from VBO 1
glDrawElements(GL_TRIANGLES, 36, GL_UNSIGNED_SHORT, 0);
}