V3 apply multiple shaders

cocos2d-x
#1

Hello.

I found interesting example in Cpp-Tests/ShaderTests, especially Effect and EffectSprite classes. Their API looks like EffectSprite can apply multiple Effects (whose are based on shaders), depending on effects priorities.

First shader (applyed first):

#ifdef GL_ES
precision highp float;
#endif

varying vec2  v_texCoord;
varying vec2  v_fragmentColor;

uniform vec3  u_lightColor;
uniform float u_lightBrightness;

void main(void)
{
    vec4 texColor = texture2D(CC_Texture0, v_texCoord);
    vec3 diffuse = u_lightBrightness * u_lightColor;
    gl_FragColor = vec4(texColor.rgb * diffuse, texColor.a);
}

Second shader:

#ifdef GL_ES
precision highp float;
#endif

varying vec2 v_texCoord;

void main(void)
{
    vec4 texColor = texture2D(CC_Texture0, v_texCoord);

    gl_FragColor = gl_FragColor; // doesnt work
    gl_FragColor = texColor; // resets the previously done work by first shader
}

My question is: how to access the texture rendered by first effect and pass it to the second one? texture2D(CC_Texture0, v_texCoord) doesnt look like a solution anyway.

2 Likes
#2

No, the effect doesn’t work as you think. If you want to do some operation based on the result of previous one, you should use RenderTexture.