OpenGL阴影贴图

2023年9月15日 297次阅读

我试图做一个基本的阴影贴图,但由于某种原因它没有正确渲染.

Video of the Problem

我使用平面着色器渲染房子：

int shadowMapWidth = WINDOW_SIZE_X * (int)SHADOW_MAP_RATIO;
int shadowMapHeight =  WINDOW_SIZE_Y * (int)SHADOW_MAP_RATIO;

// Rendering into the shadow texture.
glActiveTexture(GL_TEXTURE0);
CALL_GL(glBindTexture(GL_TEXTURE_2D, shadowTexture));
// Bind the framebuffer.
CALL_GL(glBindFramebuffer(GL_FRAMEBUFFER, shadowFBO));
//Clear it
CALL_GL(glClear(GL_DEPTH_BUFFER_BIT));
CALL_GL(glViewport(0, 0, shadowMapWidth, shadowMapHeight));
CALL_GL(glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE));
//Render stuff
flatShader.use();
flatShader["baseColor"] = glm::vec4(1.0f,1.0f,1.0f,1.0f);
flatShader["pvm"] = projectionMatrix*pointLight.viewMatrix*cursor.modelMatrix;
cursor.draw(); //binds the vao and draws

// Revert for the scene.
CALL_GL(glBindFramebuffer(GL_FRAMEBUFFER, 0));
CALL_GL(glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE));
CALL_GL(glViewport(0, 0, WINDOW_SIZE_X, WINDOW_SIZE_Y));

请注意,我只渲染房子.我没有在深度缓冲传递中渲染地板.

在此之后,我使用以下着色器对渲染表示地板的四边形：

/* [VERT] */ 
#version 330

in vec3 in_Position;
in vec2 in_TexCoord;

uniform mat4 shadowMatrix;
uniform mat4 mvp;

out vec2 UV;
out vec4 shadowProj;

void main()
{
    gl_Position = mvp*vec4(in_Position,1.0);
    shadowProj = shadowMatrix*vec4(in_Position,1.0);
    UV = in_TexCoord;
}

片段着色器：

/* [FRAG] */ 
#version 330

in vec2 UV;
in vec4 shadowProj;

out vec4 fragColor;

uniform sampler2D texturex;
uniform sampler2DShadow shadowMap;

void main()
{
    fragColor = vec4(texture(texturex, UV).rgb,1);

    float shadow = 1.0;
    shadow = textureProj(shadowMap,shadowProj);

    fragColor *= shadow;

}

然后我再次用颜色画出房子……地板：

textureShader.use();

glUniform1i(baseImageLoc, 0); //Texture unit 0 is for base images.
glUniform1i(shadowMapLoc, 1); //Texture unit 1 is for shadow maps.

glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, floorTexture);

glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, shadowTexture);
textureShader["shadowMatrix"] = projectionMatrix*pointLight.viewMatrix*floorMatrix;
textureShader["mvp"] = projectionMatrix*viewMatrix*floorMatrix;
CALL_GL(glBindVertexArray(floorVAO));
CALL_GL(glDrawArrays(GL_TRIANGLES,0,18));

glfwSwapBuffers();

以前有人见过这种行为吗？知道什么可能是错的吗？顺便说一下灯的coordaintes直接把它放在房子的顶部,所以阴影应该直接在地板上的房子下面(但它最终侧向).

这里参考我是如何生成阴影FBO的：

int shadowMapWidth = WINDOW_SIZE_X * (int)SHADOW_MAP_RATIO;
int shadowMapHeight =  WINDOW_SIZE_Y * (int)SHADOW_MAP_RATIO;

glGenTextures(1, &shadowTexture);
glBindTexture(GL_TEXTURE_2D, shadowTexture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, shadowMapWidth, shadowMapHeight, 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_BYTE, 0);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_REF_TO_TEXTURE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC, GL_LESS);
glTexImage2D(GL_TEXTURE_2D,0,GL_DEPTH_COMPONENT,shadowMapWidth,shadowMapHeight,0,GL_DEPTH_COMPONENT,GL_FLOAT,NULL);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_COMPARE_MODE,GL_COMPARE_R_TO_TEXTURE);
glBindTexture(GL_TEXTURE_2D, 0); //unbind the texture

glGenFramebuffers(1, &shadowFBO);
glBindFramebuffer(GL_FRAMEBUFFER, shadowFBO);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, shadowTexture, 0);
glDrawBuffer(GL_NONE);
glReadBuffer(GL_NONE);

if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
{ printf("GL_FRAMEBUFFER_COMPLETE error 0x%x", glCheckFramebufferStatus(GL_FRAMEBUFFER)); }

glClearDepth(1.0f); glEnable(GL_DEPTH_TEST);
// Needed when rendering the shadow map. This will avoid artifacts.
glPolygonOffset(1.0f, 0.0f); glBindFramebuffer(GL_FRAMEBUFFER, 0);
//to convert the texture coordinates to -1 ~ 1
   GLfloat biasMatrixf[] = {
    0.5f, 0.0f, 0.0f, 0.0f,
    0.0f, 0.5f, 0.0f, 0.0f,
    0.0f, 0.0f, 0.5f, 0.0f,
    0.5f, 0.5f, 0.5f, 1.0f };

biasMatrix = glm::make_mat4(biasMatrixf);

最佳答案 看起来您忘了将阴影矩阵乘以偏差矩阵.

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