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POOpenGL/GLSL - Handling lighting from an old game (mixing ambient light and vertex colors)
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copied!<p>I am writing a client that supports loading of an old game format. It uses fake lighting where for every vertex, there is often a vertex color supplied. I got the lighting to appear correctly by using:</p> <pre><code>vec4 textureColor = texture2D(texture, outtexture) * vertexColor; </code></pre> <p>The problem was that for vertices supplied that were 0.0, 0.0, 0.0 for RGB, the entire texture was of course black. I have been playing around with a few different algorithms but the textures still look a bit dark or the lights are too bright.</p> <p>Here is the shader:</p> <pre><code>float ambient = 1.0; vec4 textureColor = texture2D(texture, outtexture); vec4 lighting = vec4((vertexColor * vertexColor.a) + (ambient * textureColor)); gl_FragColor = textureColor * lighting; </code></pre> <p>Here is an example:</p> <p><img src="https://i.stack.imgur.com/8ZVrw.png" alt="Textures with no light are too dark"></p> <p>Now, the vertex color data is a bit weird too. Here's an example:</p> <pre><code><-!-> R: 0.000000, G: 0.000000, B: 0.000000, A: 0.000000 <-!-> R: 0.000000, G: 0.000000, B: 0.000000, A: 0.000000 <-!-> R: 0.000000, G: 0.000000, B: 0.000000, A: 0.000000 <-!-> R: 0.023529, G: 0.023529, B: 0.003922, A: 0.858824 <-!-> R: 0.007843, G: 0.007843, B: 0.000000, A: 0.850980 <-!-> R: 0.007843, G: 0.007843, B: 0.000000, A: 0.858824 <-!-> R: 0.023529, G: 0.023529, B: 0.003922, A: 0.858824 <-!-> R: 0.050980, G: 0.050980, B: 0.011765, A: 0.882353 <-!-> R: 0.078431, G: 0.078431, B: 0.015686, A: 0.858824 <-!-> R: 0.078431, G: 0.078431, B: 0.015686, A: 0.858824 <-!-> R: 0.050980, G: 0.050980, B: 0.011765, A: 0.894118 <-!-> R: 0.031373, G: 0.031373, B: 0.007843, A: 0.862745 <-!-> R: 0.050980, G: 0.050980, B: 0.011765, A: 0.882353 <-!-> R: 0.050980, G: 0.050980, B: 0.011765, A: 0.894118 <-!-> R: 0.031373, G: 0.031373, B: 0.007843, A: 0.858824 <-!-> R: 0.000000, G: 0.000000, B: 0.000000, A: 0.858824 <-!-> R: 0.000000, G: 0.000000, B: 0.000000, A: 0.835294 </code></pre> <p>Notice that it contains some normal values (0, 0, 0, 0) and some regular ones with decimal numbers as well as values that are 0, 0, 0 and then have an alpha defined.</p> <p>Feel free to chime in if you have seen this method or have any suggestions for how to achieve a normal looking render. Yes, I realize this question is a bit different but hopefully someone should have some insight.</p> <p>Edit: If this helps at all, a friend of mine had a similar project. This was how he loaded the information and packaged it for DirectX:</p> <pre><code> int iBlue = GetByte( ); int iGreen = GetByte( ); int iRed = GetByte( ); int iAmb = GetByte( ); pVertex->m_dwDiffuse = D3DCOLOR_ARGB( (BYTE)( max( iAmb, 1 ) ), (BYTE)( max( iRed, 1 ) ), (BYTE)( max( iGreen, 1 ) ), (BYTE)( max( iBlue, 1 ) ) ); </code></pre> <p>I am assuming he does exactly what I do and converts the bytes to integers and then if they are negative, he replaces them with 1. Still wish I knew how he used them while rendering...</p> <p>What it's supposed to look like:</p> <p>Day (Much less/almost no light being seen) <img src="https://i.stack.imgur.com/Y6djc.png" alt="enter image description here"></p> <p>Night:</p> <p><img src="https://i.stack.imgur.com/GGu1Z.png" alt="enter image description here"></p> <p>Mine (with the above shader code): <img src="https://i.stack.imgur.com/9QoFP.png" alt="enter image description here"></p> <p>It appears that the lights are either too bright or their black contribution to the textures makes them too hard to see.</p>

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