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POChanging level of opacity in OpenGL ES 2.0
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2013-03-28T22:06:55.870
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2013-04-10T00:42:59.800
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2017-04-13T12:18:41.660
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EDIT 1: Included shaders EDIT 2: Included screen-shots EDIT 3: Included screen-shot of original texture EDIT 4: EDIT 5: I think the problem is because my bitmaps have partially transparent pixels in them to start with, so I will ask a new question as the answer given here is correct for this question. On closer inspection, the problem doesn't quite appear to be resolved, colours aren't looking correct. <pre><code>String strFShader = "precision mediump float;" + "uniform float Opacity;" + "varying vec2 v_texCoords;" + "uniform sampler2D u_baseMap;" + "void main()" + "{" + "gl_FragColor = texture2D(u_baseMap, v_texCoords);" + "gl_FragColor.a *= Opacity;"+ "}"; </code></pre> And then in my rendering method: <pre><code> //Enable and set mode GLES20.glEnable(GLES20.GL_BLEND); GLES20.glBlendFunc(GLES20.GL_SRC_ALPHA, GLES20.GL_ONE_MINUS_SRC_ALPHA); //Draw GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4); //Disable GLES20.glDisable(GLES20.GL_BLEND); </code></pre> So, at max transparency (0.0), it's all good, i.e. nothing gets drawn. However at any other level it's not quite right, For example, at zero transparency (opacity set to 1.0), this is what I get: ![enter image description here][1] But it should actually look like this: ![enter image description here][2] Colours looks a little too dark and, (on the original image), the ever so slightly dark edge is really pronounced. I'm assuming it's something to do with the blending mode? Basically I'm simply after the effect one might get in photoshop when changing the opacity of one layer over another. Any other suggestions would be very helpful. I also tried the solution found here: <a href="https://gamedev.stackexchange.com/questions/7260/opengl-es-basic-fragment-shader-help-with-transparency">https://gamedev.stackexchange.com/questions/7260/opengl-es-basic-fragment-shader-help-with-transparency</a> But I get the same results? Thanks :-)
Tags
<android><opengl-es-2.0><opacity><sprite>
Title
Changing level of opacity in OpenGL ES 2.0
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