动态更改GLSL着色器中的参数值 [英] Changing the parameter value in GLSL shader dynamically
问题描述
您好,
是否可以在运行时动态发送片段着色器的gl_FragColor.a值。例如,用户在文本框中输入alpha值,该值将分配给gl_FragColor.a变量;
我的片段着色器代码是
void main()
{
gl_FragColor = gl_Color;
gl_FragColor.a = 0.2; //这里是静态分配的,但是我需要将它分配给
//给定文本框的用户值。可能吗??
}
感谢您的帮助。
Arpan
Hello,
Is it possible to send the gl_FragColor.a value for fragment shader dynamically on the runtime. say for example, user input the alpha value in a text box and the value will be assigned to the gl_FragColor.a variable;
my fragment shader code is
void main()
{
gl_FragColor = gl_Color;
gl_FragColor.a = 0.2; // here it is assigned statically but i need to assign it so
// value from the user given textbox. Is it possible??
}
Thank you for your help.
Arpan
推荐答案
请在你的glsl着色器程序中添加一个统一参数。
然后使用glGetUniformLocation将值设置为此参数[将参数id设置为cpp程序]和glUniform [改变参数的值]
Please add a uniform parameter in your glsl shader program.
Then set value to this parameter using glGetUniformLocation[To get the parameter id to cpp program] and glUniform [To change the value of parameter]
// This value can be changed before rendering a frame.
// Whenever you need to change you can change value of this parameter
uniform float fAlphaValueByUser_i;
void main()
{
gl_FragColor = gl_Color;
gl_FragColor.a = fAlphaValueByUser_i; // Change output alpha color with input float value
}
// cpp code.
GLint nAlphaLocation = glGetUniformLocation( m_ProgramID, "fAlphaValueByUser_i" );
glUniform1f( nAlphaLocation, fAlphaValueFromGUI );
我发现在计算顶点着色器中的位置时遇到了一些错误。它适用于Santhosh G_方法。
I found out that I had some mistake in calculating position in vertex shader. It works fine accroding to Santhosh G_ method.
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