Getting started with QT & OpenGL

Catalog

8、 ... and 、 Matrix transformation

---

Introduction chapter

One 、 Window building

  Add the style

  add to OpenGL Area

Create a new class Convenient for OpenGLwidget The operation of . Inherited classes can be changed  

Control promotion

  add to , Choose promote

Two 、 Draw triangle

triangle graphic data

 

 

 

  After binding Drawing

glDrawArrays(GL_TRIANGLES,0,6);  // from 0 Start looking for 6 A little bit 

3、 ... and 、 Compile and connect fixed-point shaders

Before drawing figures Using shaders ,VBO Actual stored data ,VAO Store a series of operations

Index buffer object EBO

Switch to 4 A little bit

 

 

 

  stay EBO After binding Then untie VAO

 

VAO Record EBO Unbind operation   Cannot draw , but VAO Don't record VBO Unbundling

Four 、 Interaction control

 

 

 

 

  The interface already has You also need to call

 

Change the drawing style

  

5、 ... and 、QT External use Shaders

 

Coding rule settings

  Include header file

  link

  The difference in use

  Delete EBO 

6、 ... and 、 Shader explanation

Assembly line Input and output

 

 

Input and output

  Rely on the name Transfer data on the pipeline , Fixed point shaders Pass to Fragment Shader

Fixed point shaders

layout (location = 0) in vec3 aPos;  Indexes

 

 

  inquiry apos Location

  Binding method Location

 

 uniform

 

 

If not called resize paint When to quit Will report a mistake

  Multiple attributes   0=position 1=color

glVertexAttribPointer();  // Offset 

 

 

 

 

7、 ... and 、 Texture loading

Tell the triangle that a certain point needs to be loaded Which point of the texture pattern

 

 

  Texture units 0 

 

 QT It's encapsulated You can use it directly QT encapsulation

 

 

  When adding textures VAO Final unbinding Easy to record

 

  The channel is 0 So binding 0  

  Add a reddening effect

 

 

  Loading of multiple textures    

 CPU End separation

  Activate the channel 1

  Texture wrapping

 

 

 

  Texture filtering

8、 ... and 、 Matrix transformation

 

 

 

  Rotate first and then move , Zoom in first and then shift

The vertices In the shader

 

 

 

Nine 、 Coordinate system

Ten

...