如何在 OpenGL Android 中同时实现亮度和对比度滤镜？

Question

我有2个代码，一个用于亮度，一个用于对比度如下。

亮度

"precision mediump float;" +
            " varying vec2 vTextureCoord;\n" +
            " \n" +
            " uniform lowp sampler2D sTexture;\n" +
            " uniform lowp float brightness;\n" +
            " \n" +
            " void main()\n" +
            " {\n" +
            "     lowp vec4 textureColor = texture2D(sTexture, vTextureCoord);\n" +
            "     \n" +
            "     gl_FragColor = vec4((textureColor.rgb + vec3(brightness)), textureColor.w);\n" +
            " }";

 @Override
    public void onDraw() {
        GLES20.glUniform1f(getHandle("brightness"), this.brightness);
    }

对比度

"precision mediump float;" +
            " varying vec2 vTextureCoord;\n" +
            " \n" +
            " uniform lowp sampler2D sTexture;\n" +
            " uniform lowp float contrast;\n" +
            " \n" +
            " void main()\n" +
            " {\n" +
            "     lowp vec4 textureColor = texture2D(sTexture, vTextureCoord);\n" +
            "     \n" +
            "     gl_FragColor = vec4(((textureColor.rgb - vec3(0.5)) * contrast + vec3(0.5)), textureColor.w);\n" +
            " }";

   @Override
    public void onDraw() {
        GLES20.glUniform1f(getHandle("contrast"), this.contrast);
    }

完成一个过滤器

public class GlBrightnessFilter extends GlFilter {
    private static final String BRIGHTNESS_FRAGMENT_SHADER = "" +
            "precision mediump float;" +
            " varying vec2 vTextureCoord;\n" +
            " \n" +
            " uniform lowp sampler2D sTexture;\n" +
            " uniform lowp float brightness;\n" +
            " \n" +
            " void main()\n" +
            " {\n" +
            "     lowp vec4 textureColor = texture2D(sTexture, vTextureCoord);\n" +
            "     \n" +
            "     gl_FragColor = vec4((textureColor.rgb + vec3(brightness)), textureColor.w);\n" +
            " }";

    public GlBrightnessFilter() {
        super(DEFAULT_VERTEX_SHADER, BRIGHTNESS_FRAGMENT_SHADER);
    }

    private float brightness = 0f;

    public void setBrightness(float brightness) {
        this.brightness = brightness;
    }
    public void setContrast(float contrast) {
        this.contrast = contrast;
    }
    @Override
    public void onDraw() {
        GLES20.glUniform1f(getHandle("brightness"), brightness);
    }
}

如何在不清除其他过滤器的情况下合并它们以更改两者。我希望在不更改其他过滤器值的情况下更改两者。

基本上我希望使用单个过滤器来更改两个值。

Answer 1

"precision mediump float;" +
            " varying vec2 vTextureCoord;\n" +
            " \n" +
            " uniform lowp sampler2D sTexture;\n" +
            " uniform lowp float brightness;\n" +
            " uniform lowp float contrast;\n" +
            " \n" +
            " void main()\n" +
            " {\n" +
            "     lowp vec4 textureColor = texture2D(sTexture, vTextureCoord);\n" +
            "     \n" +
            "     gl_FragColor = vec4(((textureColor.rgb - vec3(0.5)) * contrast + vec3(0.5)) + vec3(brightness), textureColor.w);\n" +
            " }";

如何在 OpenGL Android 中同时实现亮度和对比度滤镜？

How to implement both brightness and contrast filter together in OpenGL Android?

android

opengl-es