将影子地图发送到OpenGL中的着色器

Question

我试图在场景中实现阴影映射，但是当我调用texture()时，我得到的只是片段着色器中的零(我已经用== 0.0对其进行了测试(。我的问题：我是否正确地将深度纹理发送到着色器？

这是我的片段着色器代码：

bool getShadow() {
    vec4 lightProjPositionScaled = lightProjPosition/lightProjPosition.w;
    vec2 texCoords = lightProjPositionScaled.xy*0.5 + 0.5;  // bias
    return lightProjPositionScaled.z + 0.0005 > texture(shadowMap, texCoords).x;
}

这是我相关的Java代码
INIT(由于BDL的评论而编辑(

gl.glEnable(GL2.GL_TEXTURE_2D);
// generate stuff
IntBuffer ib = IntBuffer.allocate(1);
gl.glGenFramebuffers(1, ib);
frameBuffer = ib.get(0);
ib = IntBuffer.allocate(1);
gl.glGenTextures(1, ib);
shadowMap = ib.get(0);
gl.glBindFramebuffer(GL2.GL_FRAMEBUFFER, frameBuffer);
gl.glBindTexture(GL2.GL_TEXTURE, shadowMap);
gl.glTexImage2D(GL2.GL_TEXTURE_2D, 0, GL2.GL_DEPTH_COMPONENT, 1024, 1024, 0, GL2.GL_DEPTH_COMPONENT, GL2.GL_FLOAT, null);
gl.glDrawBuffer(GL2.GL_NONE);
gl.glReadBuffer(GL2.GL_NONE);
gl.glBindFramebuffer(GL2.GL_FRAMEBUFFER, 0);

// prevents 'shadow acne'
gl.glPolygonOffset(2.5f, 0);
// prevents multiple shadows
gl.glTexParameteri(GL2.GL_TEXTURE_2D, GL2.GL_TEXTURE_WRAP_S, GL2.GL_CLAMP_TO_EDGE);
gl.glTexParameteri(GL2.GL_TEXTURE_2D, GL2.GL_TEXTURE_WRAP_T, GL2.GL_CLAMP_TO_EDGE);
// prevents (or expects!!!) pixel-y textures
gl.glTexParameteri(GL2.GL_TEXTURE_2D, GL2.GL_TEXTURE_MIN_FILTER, GL2.GL_NEAREST);
gl.glTexParameteri(GL2.GL_TEXTURE_2D, GL2.GL_TEXTURE_MAG_FILTER, GL2.GL_NEAREST);
// store one value in all four components of pixel
gl.glTexParameteri(GL2.GL_TEXTURE_2D, GL2.GL_DEPTH_TEXTURE_MODE, GL2.GL_INTENSITY);

显示(第1遍，用于阴影(：

// render shadows
gl.glUseProgram(shadowProgram);
gl.glUniformMatrix4fv(lightMatrixLocShadow, 1, false, lightMatrix.getMatrix(), 0);  // yep (haha change viewMatrix -> lightMatrix)
gl.glUniformMatrix4fv(projMatrixLocShadow, 1, false, projMatrix.getMatrix(), 0);
gl.glBindFramebuffer(GL2.GL_FRAMEBUFFER, sha.frameBuffer);
gl.glViewport(0, 0, 1024, 1024);
gl.glClear(GL2.GL_DEPTH_BUFFER_BIT);
renderScene(gl, sunMatrix);
gl.glCopyTexImage2D(GL2.GL_TEXTURE_2D, 0, GL2.GL_DEPTH_COMPONENT, 0, 0, 1024, 1024, 0);
gl.glBindFramebuffer(GL2.GL_FRAMEBUFFER, 0);

显示(第二通过，用于渲染场景(：

// render display (regular)
gl.glUseProgram(displayProgram);
gl.glDrawBuffer(GL2.GL_FRONT);
gl.glReadBuffer(GL2.GL_FRONT);
gl.glUniformMatrix4fv(viewMatrixLoc, 1, false, viewMatrix.getMatrix(), 0);
gl.glUniformMatrix4fv(projMatrixLocDisplay, 1, false, projMatrix.getMatrix(), 0);
gl.glUniformMatrix4fv(lightMatrixLocDisplay, 1, false, lightMatrix.getMatrix(), 0);
gl.glUniform4fv(sunPositionLoc, 1, sunWorldPosition, 0);    // send sun's position to shader
gl.glUniform1f(sunBrightnessLoc, sunBrightness);
gl.glUniform1i(shadowMapLoc, 0);
gl.glViewport(0, 0, screenWidth, screenHeight);
// day-night cycle
float[] color = SkyManager.getSkyColor(time);
gl.glClearColor(color[0], color[1], color[2], 1);
gl.glClear(GL2.GL_COLOR_BUFFER_BIT | GL2.GL_DEPTH_BUFFER_BIT);
gl.glActiveTexture(GL2.GL_TEXTURE0);
gl.glBindTexture(GL2.GL_TEXTURE_2D, sha.shadowMap);
renderScene(gl, sunMatrix);

另一个奇怪的结果是，仅z=0平面上的片段相对于光矩阵(灯的旋转，平面随之旋转(才被点亮。所有其他碎片在光线后面和前面都被遮蔽。

Answer 1

一个问题是线gl.glBindTexture(GL2.GL_TEXTURE, shadowMap);

我将纹理绑定到GL_TEXTURE而不是GL_TEXTURE_2D。