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我想在我的場景中實現陰影貼圖,但是當我調用texture()
(我已用== 0.0
測試過)時,我得到的是片段着色器中的零。我的問題:我是否正確地將深度紋理髮送給着色器?在OpenGL中發送陰影貼圖到着色器
這裏是我的片段着色器代碼:
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;
}
這裏是我相關的Java代碼
初始化(編輯由於BDL的評論)
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);
顯示(一號通,對陰影):
// 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);
顯示器(第二遍,用於渲染場景):
// 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);
另一個奇怪的結果是相對於光矩陣(光的旋轉和平面隨其旋轉的平面)上的只有碎片被點亮。所有其他碎片,在光線之後和之前,都被遮蔽了。
你在檢查OpenGL錯誤的地方嗎?我從第一個角度看至少有兩個發生。 'GL_RENDERBUFFER'不是'glBindTexture'支持的目標。你永遠不會將紋理附加到幀緩衝區('glFramebufferTexture2D'),所以它很可能不完整。檢查'glCheckFramebufferStatus'。 – BDL
啊我切換到使用渲染緩衝區,然後切換回使用紋理。當使用'glCheckFramebufferStatus'時,我得到'GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT'。 – clabe45
是的,因爲你從未附加深度紋理......並且在檢查之前你必須調用'glDrawBuffer(GL_NONE)',否則需要顏色附件。 – BDL