155 lines
5.0 KiB
C++
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);
|
|
}
|