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我有一个由很多对象组成的场景，当我渲染它们时，我会遍历场景中的所有项目并在它们上调用 glDrawElements。这工作正常。但是，现在我正在实现场景的阴影映射，并且使用相同的方式绘制到阴影缓冲区。但是，只有场景中的第一个元素以正确的方式绘制到纹理，我通过将深度纹理附加到场景元素来检查这一点，您将在下面看到。

代码如下：

glBindFramebuffer(GL_FRAMEBUFFER, vFrameBuffers[ShadowFB]);
glViewport(0,0,1024,1024);

glClearDepth(1.0f);
glClear(GL_DEPTH_BUFFER_BIT);

glUseProgram(shadowShader);
depth_loc = glGetUniformLocation(shadowShader, "depthProj");
model_view_loc = glGetUniformLocation(shadowShader, "modelmat");

glUniformMatrix4fv(depth_loc, 1, GL_FALSE, depthproj);

depthproj = mat4(1.0);
depthproj = Ortho(-250.0f, 250.0f, -200.0f, 200.0f, -200.0f, 200.0f);
depthproj = depthproj * RotateX(15);
depthproj = depthproj * RotateY(220);

for (int i = 0; i < _objectArray.size(); i++)
{
    modelmat = mat4(1.0);
    modelmat = modelmat*Translate(_objectArray[i]->getLocation()->getX(),
        _objectArray[i]->getLocation()->getY(),
        _objectArray[i]->getLocation()->getZ());

    glUniformMatrix4fv(model_view_loc, 1, GL_FALSE, modelmat);

    if (_objectArray[i]->getType() == TypeMountain)
    {
        glBindVertexArray(vArrays[ShadowMountainA]);
        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vElements[ShadowMountainE]);
        glDrawElements(GL_TRIANGLES, 40*40*6, GL_UNSIGNED_SHORT, NULL);
        glBindVertexArray(0);
    }
    else if (_objectArray[i]->getType() == TypePasture)
    {   
        glBindVertexArray(vArrays[ShadowPastureA]);
        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vElements[ShadowPastureE]);
        glDrawElements(GL_TRIANGLES, 40*40*6, GL_UNSIGNED_SHORT, NULL);
        glBindVertexArray(0);
    }
    else if (_objectArray[i]->getType() == TypeWater)
    {   
        glBindVertexArray(vArrays[ShadowWaterA]);
        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vElements[ShadowWaterE]);
        glDrawElements(GL_TRIANGLES, 40*40*6, GL_UNSIGNED_SHORT, NULL);
        glBindVertexArray(0);
    }
    else if (_objectArray[i]->getType() == TypeTree)
    {   
        glBindVertexArray(vArrays[ShadowTreeA]);
        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vElements[ShadowTreeE]);
        glDrawElements(GL_TRIANGLES, 180, GL_UNSIGNED_SHORT, NULL);
        glBindVertexArray(0);
    }
}

glUseProgram(0);

当我只在山对象上运行它时，这是我得到的结果图像，你可以看到它是正确的。 帧缓冲区中的山 它也单独适用于其他场景元素。我的问题是如何使用多次绘制在同一个缓冲区中毫无问题地绘制？

编辑：只是因为这里要求的是阴影着色器组件：

顶点着色器：

#version 330 core

uniform mat4 depthProj;
uniform mat4 modelmat;

layout(location = 0) attribute vec4 vPosition;

void main()
{
    gl_Position = depthProj * modelmat * vPosition;
}

片段着色器：

#version 330 core

layout(location = 0) out float fragmentDepth;

void main()
{
}
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1 回答 1

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I don't know why, but when the lines,

glUniformMatrix4fv(depth_loc, 1, GL_FALSE, depthproj);

and

glUniformMatrix4fv(model_view_loc, 1, GL_FALSE, modelmat);

are turned into;

glUniformMatrix4fv(depth_loc, 1, GL_TRUE, depthproj);

and

glUniformMatrix4fv(model_view_loc, 1, GL_TRUE, modelmat);

the scene is drawn as it should.

于 2014-04-27T03:33:38.967 回答