我遇到了我在着色器体验中遇到过的最奇怪的问题 . 我创建了一些测试着色器代码（见下文）并在一个简单的纹理上运行它 .
基本上我试图做的是让我的着色器检查片段的颜色，如果它在一定范围内，它将根据统一的颜色变量为该片段着色 . 我遇到的问题是我的着色器无法正确识别片段的颜色 . 我甚至还去检查颜色的红色部分是否等于1，并且每个片段总是返回true . 然而，如果我使用相同的着色器绘制原始纹理，它就可以正常工作 .
为什么会这样？着色器编译时没有任何错误 . 我觉得我错过了一些明显的东西......
代码（如果您有权访问LibGDX，您可以自己运行此代码） .
// Vertex
#version 330
in vec4 a_position;
in vec4 a_color;
in vec2 a_texCoord0;
out vec4 v_color;
out vec2 v_texCoord0;
uniform mat4 u_projTrans;
void main() {
v_color = a_color;
v_texCoord0 = a_texCoord0;
gl_Position = u_projTrans * a_position;
}
// Fragment
#version 330
in vec4 v_color;
in vec2 v_texCoord0;
out vec4 outColor;
uniform vec4 color;
uniform sampler2D u_texture;
void main() {
// This is always true for some reason...
if(v_color.r == 1.0) {
outColor = color;
} else {
// But if I run this code it draws the original texture just fine with the correct colors.
outColor = v_color * texture2D(u_texture, v_texCoord0);
}
}
// Java code.
// Creating sprite, shader and sprite batch.
SpriteBatch batch = new SpriteBatch();
Sprite sprite = new Sprite(new Texture("testTexture.png"));
ShaderProgram shader = new ShaderProgram(Gdx.files.internal("vertex.vert"),
Gdx.files.internal("fragment.frag"));
// Check to see if the shader has logged any errors. Prints nothing.
System.out.println(shader.getLog());
// We start the rendering.
batch.begin();
// We begin the shader so we can load uniforms into it.
shader.begin();
// Set the uniform (works fine).
shader.setUniformf("color", Color.RED);
// We end the shader to tell it we've finished loading uniforms.
shader.end();
// We then tell our renderer to use this shader.
batch.setShader(shader);
// Then we draw our sprite.
sprite.draw(batch);
// And finally we tell our renderer that we're finished drawing.
batch.end();
// Dispose to release resources.
shader.dispose();
batch.dispose();
sprite.getTexture().dispose();
纹理：
1 回答
片段着色器有2种输入颜色：一种作为顶点属性发送，另一种作为纹理发送 . 您打算检查纹理颜色，而是检查作为顶点属性发送的颜色值 .