我绘制了一个彩色的四边形，但是当我尝试应用正交投影时，我看不到它（我只看到空的绿色屏幕，仅使用模型矩阵就可以了）屏幕尺寸为500x500。类似的问题并没有帮助我找出解决方案（调整线的大小，替换四边形的顶点等）
public class BaseFrame implements GLEventListener
{
private int screenWidth;
private int screenHeight;
private Shader shader;
private OpenGlObject myObj;
public BaseFrame(Dimension dim){
this.screenWidth = dim.width;
this.screenHeight = dim.height;
}
public void init(GLAutoDrawable glAutoDrawable) {
GL3 gl = glAutoDrawable.getGL().getGL3();
//-----------------------SHADER TEST------------------------
String[] vertexShaderSource = new String[1];
vertexShaderSource[0] = "#version 330\n" +
"layout(location=0) in vec2 position;\n" +
"layout(location=1) in vec3 color;\n" +
"out vec4 vColor;\n" +
"uniform mat4 model;" +
"uniform mat4 projection;" +
"void main(void)\n" +
"{\n" +
"gl_Position = projection * model * vec4(position, 0.0, 1.0);\n" +
"vColor = vec4(color, 1.0);\n" +
"}\n";
String[] fragmentShaderSource = new String[1];
fragmentShaderSource[0] = "#version 330\n" +
"in vec4 vColor;\n" +
"out vec4 fColor;\n" +
"void main(void)\n" +
"{\n" +
"fColor = vColor;\n" +
"}\n";
shader = new Shader(gl);
shader.compile(vertexShaderSource,fragmentShaderSource,null);
Mat4 projection = Matrices.ortho(0.0f, (float)screenWidth, (float)screenHeight,
0.0f, -1.0f, 1.0f);
System.out.println(projection.toString());
shader.setMatrix4f("projection", projection, false);
//--------------------------------------------------------
gl.glEnableClientState(GL2.GL_VERTEX_ARRAY);
gl.glClearColor(0.0f, 1.0f, 0.0f, 0.0f);
myObj = new OpenGlObject( 2, 6, gl);
myObj.initRenderData(new float[]{0.0f, 100f,
100f, 0.0f,
0.0f, 0.0f,
0.0f, 100f,
100f, 100f,
100f, 100f},
new float[]{0.1f, 0.2f, 0.3f,
0.6f, 0.5f, 0.4f,
0.0f, 0.0f, 0.0f,
2.0f, 1.0f, 3.0f,
0.0f, 0.0f, 0.0f,
0.7f, 0.8f, 0.9f});
System.out.println(gl.glGetError() + " init end");
}
public void dispose(GLAutoDrawable glAutoDrawable) {
}
public void display(GLAutoDrawable glAutoDrawable) {
GL3 gl = glAutoDrawable.getGL().getGL3();
gl.glClear(GL3.GL_DEPTH_BUFFER_BIT | GL3.GL_COLOR_BUFFER_BIT);
System.out.println(gl.glGetError() + " display0");
System.out.println(gl.glGetError() + " display1");
myObj.draw(0.0f, 0.0f, shader);
System.out.println(gl.glGetError() + " display2");
}
public void reshape(GLAutoDrawable glAutoDrawable, int i, int i1, int i2, int i3) {
}
}
OpenGLObject
public class OpenGlObject {
private final GL3 gl;
private int buffersFilled;
private int buffersCount;
private int verticesCount;
private IntBuffer buffers;
private IntBuffer vertexArray;
private ArrayList<Integer> paramsCount;
//BufferParamsCount states for number of buffers the object will have (i.e. vertices, colors and etc.)
public OpenGlObject(int bufferParamsCount, int verticesCount, GL3 gl) {
this.gl = gl;
this.buffersFilled = 0;
this.buffersCount = bufferParamsCount;
this.verticesCount = verticesCount;
this.buffers = IntBuffer.allocate(buffersCount);
this.vertexArray = IntBuffer.allocate(1);
this.paramsCount = new ArrayList<>();
}
public void initRenderData(float[]... dataArrays){
addBuffers(dataArrays);
genVertexArray();
}
public void addBuffers(float[]... dataArrays){
gl.glGenBuffers(buffersCount,buffers);
for(float[] fData : dataArrays) {
FloatBuffer floatBuffer = FloatBuffer.wrap(fData);
gl.glBindBuffer(GL3.GL_ARRAY_BUFFER, this.buffers.get(buffersFilled++));
gl.glBufferData(GL3.GL_ARRAY_BUFFER, 4 * fData.length, floatBuffer, GL3.GL_STATIC_DRAW);
paramsCount.add(fData.length / this.verticesCount);
}
System.out.println(gl.glGetError() + " addBuffers");
}
private void genVertexArray(){
gl.glGenVertexArrays(1, this.vertexArray);
gl.glBindVertexArray(this.vertexArray.get(0));
for(int i = 0; i < this.buffersFilled; i++){
gl.glEnableVertexAttribArray(i);
gl.glBindBuffer(GL3.GL_ARRAY_BUFFER, buffers.get(i));
gl.glVertexAttribPointer(i, this.paramsCount.get(i), GL.GL_FLOAT, false, 0, 0);
}
System.out.println(gl.glGetError() + " genVertexArray");
}
public void draw(float x, float y, Shader shader){
shader.use();
Mat4 model = Mat4.MAT4_IDENTITY;
model = model.translate(new Vec3(x,y,0.0f));
shader.setMatrix4f("model", model, false);
System.out.println(gl.glGetError() + " draw0");
gl.glBindVertexArray(this.vertexArray.get(0));
gl.glDrawArrays(GL.GL_TRIANGLES, 0, this.verticesCount);
System.out.println(gl.glGetError() + " draw1");
}
}
正交矩阵实现
public static final Mat4 ortho(float left, float right, float bottom, float top, float zNear, float zFar) {
float m00 = 2.0F / (right - left);
float m11 = 2.0F / (top - bottom);
float m22 = -2.0F / (zFar - zNear);
float m30 = -(right + left) / (right - left);
float m31 = -(top + bottom) / (top - bottom);
float m32 = -(zFar + zNear) / (zFar - zNear);
return new Mat4(m00, 0.0F, 0.0F, 0.0F, 0.0F, m11, 0.0F, 0.0F, 0.0F, 0.0F, m22, 0.0F, m30, m31, m32, 1.0F);
}
答案 0 :(得分：0)
问题是我在初始化函数的范围内声明了Mat4 projection。正确的做法是在绘制之前（在display函数中）将矩阵传递给着色器。
public void display(GLAutoDrawable glAutoDrawable) {
GL3 gl = glAutoDrawable.getGL().getGL3();
gl.glClear(GL3.GL_DEPTH_BUFFER_BIT | GL3.GL_COLOR_BUFFER_BIT);
Mat4 projection = Matrices.ortho(0.0f, (float)screenWidth, (float)screenHeight,
0.0f, 0.0f, 1.0f);
shader.setMatrix4f("projection", projection, false);
myObj.draw(5.0f, 5.0f, 100f, 100f, 0.0f, shader);
}
OpenGLObject的绘制函数也进行了更改，以便能够进行大小调整和旋转
public void draw(float x, float y, float xSize, float ySize, float rotationAngle, Shader shader){
shader.use();
Mat4 model = Mat4.MAT4_IDENTITY;
Mat4 rotation = Matrices.rotate(rotationAngle, new Vec3(0.0f,0.0f,1.0f));
Mat4 scale = new Mat4(xSize, 0.0f, 0.0f, 0.0f,
0.0f, ySize, 0.0f, 0.0f,
0.0f, 0.0f, 1.0f, 0.0f,
0.0f, 0.0f, 0.0f, 1.0f);
model = model.translate(new Vec3(x,y,0.0f));
model = model.translate(new Vec3(0.5f * xSize, 0.5f * ySize, 0.0f));
model = model.multiply(rotation);
model = model.translate(new Vec3(-0.5f * xSize, -0.5f * ySize, 0.0f));
model = model.multiply(scale);
shader.setMatrix4f("model", model, false);
System.out.println(gl.glGetError() + " draw0");
gl.glBindVertexArray(this.vertexArray.get(0));
gl.glDrawArrays(GL.GL_TRIANGLES, 0, this.verticesCount);
System.out.println(gl.glGetError() + " draw1");
}