bantherewind

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About bantherewind

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  1. Deferred shading - light accumulation issue

    Well, now I feel like an idiot. I had a typo in the C++ when setting the uniform for my position texture (was spelled "texPositon"). My position was always 0,0,0 which gave me a bad falloff value. Thanks for the help! It's subtle, but this has two point lights and a directional light blending nicely. And I can see it from far away. [img]http://public.gamedev.net//public/style_emoticons/default/biggrin.png[/img] [img]http://bantherewind.com/uploads/accum_08_sm.jpg[/img] [img]http://bantherewind.com/uploads/accum_09_sm.jpg[/img]
  2. Deferred shading - light accumulation issue

    Must have posted at the same time. Played with culling earlier, but will give this a shot.
  3. Deferred shading - light accumulation issue

    So here's the new issue. The lights are blending into each other better (see fig. 1), but I have to be inside (or almost inside) the sphere. Everything goes black if I back out (see fig.2 and fig. 3). The [font=courier new,courier,monospace]falloff[/font] variable in my fragment shader is controlling how much to mix the color. This should should be determined by how far the current light vertex is away from the position sampled from the G-buffer. Both are calculated using [font=courier new,courier,monospace]gl_ModelViewProjectionMatrix * gl_Vertex[/font], so the values remain relative. I'm not sure if the camera's position is somehow reducing this distance or there is something inherent in drawing these spheres that is blocking the view of what's inside. Fig .1 Lights are now blending into each other [img]http://bantherewind.com/uploads/accum_05_sm.jpg[/img] Fig.2 Image gets darker from outside [img]http://bantherewind.com/uploads/accum_06_sm.jpg[/img] Fig. 3 Light position when the image gets too dark to see. [img]http://bantherewind.com/uploads/accum_07_sm.jpg[/img]
  4. Deferred shading - light accumulation issue

    Got it! Needed to disable depth testing. The lights are blending, but now it seems I can only see from "inside" the lights, or close to it. If I zoom out, I would expect the scene to be illuminated, but smaller. Instead it goes black, as if the only visible area is inside the sphere.
  5. Deferred shading - light accumulation issue

    Additive blending is actually enabled in the above photos. Hmmm...
  6. I'm working on deferred shading and all has gone well until it comes time to render multiple lights. The first shader pass renders my scene to a G-buffer with color (albedo), position, normal, and material (specular, etc) data written to color attachments. The next shader passes create and blur a SSAO texture from the normal data and a randomizer, and it looks nice. Then I do the final lighting pass. I start experimenting by rendering out a sphere to represent a large point light (see fig. 1) and it looks mostly like what I would expect. So far so good. My goal is to draw a ton of lights in my scene. When I add a second light, it occludes the first (see fig. 2). I've tried using [font=courier new,courier,monospace]glAccum()[/font] to no avail. When I render a second light which overlaps the first in screen space (see fig. 3 and fig. 4), that pixel is overwritten. I'm having trouble understanding how to create and display a light accumulation buffer in a single shader pass. I could ping-pong FBOs between lights, but that seems like it would be really slow, and has not been suggested in any material I've read. My vertex shader (see fig. 5) and fragment shader (see fig. 6) in my lighting pass are below. Fig 1. One light [img]http://bantherewind.com/uploads/accum_01_sm.jpg[/img] Fig 2. Two lights, occluding instead of accumulating [img]http://bantherewind.com/uploads/accum_02_sm.jpg[/img] Fig 3. Spheres representing lights [img]http://bantherewind.com/uploads/accum_04_sm.jpg[/img] Fig 4. Zoom out of fig. 3 [img]http://bantherewind.com/uploads/accum_03_sm.jpg[/img] Fig. 5 Lighting pass vertex shader [CODE] varying vec4 lightPosition; void main( void ) { lightPosition = gl_ModelViewProjectionMatrix * gl_Vertex; gl_Position = lightPosition; } [/CODE] Fig. 6 Lighting pass fragment shader [CODE] uniform vec3 eyePoint; // Camera eye point uniform vec4 lightAmbient; // Light ambient color uniform vec3 lightCenter; // Center of light shape uniform vec4 lightDiffuse; // Light diffuse color uniform float lightRadius; // Size of light uniform vec4 lightSpecular; // Light specular color uniform vec2 pixel; // To convert pixel coords to [0,0]-[1,1] uniform sampler2D texAlbedo; // Color data uniform sampler2D texMaterial; // R=spec level, G=spec power, B=emissive uniform sampler2D texNormal; // Normal-depth map uniform sampler2D texPosition; // Position data uniform sampler2D texSsao; // SSAO varying vec4 lightPosition; // Position of current vertex in light void main() { // Get screen space coordinate vec2 uv = gl_FragCoord.xy * pixel; // Sample G-buffer vec4 albedo = texture2D( texAlbedo, uv ); vec4 material = texture2D( texMaterial, uv ); vec4 normal = texture2D( texNormal, uv ); vec4 position = texture2D( texPosition, uv ); vec4 ssao = texture2D( texSsao, uv ); // Calculate reflection vec3 eye = normalize( -eyePoint ); vec3 light = normalize( lightCenter.xyz - position.xyz ); vec3 reflection = normalize( -reflect( light, normal.xyz ) ); // Calculate light values vec4 ambient = lightAmbient; vec4 diffuse = clamp( lightDiffuse * max( dot( normal.xyz, light ), 0.0 ), 0.0, 1.0 ); vec4 specular = clamp( material.r * lightSpecular * pow( max( dot( reflection, eye ), 0.0 ), material.g ), 0.0, 1.0 ); vec4 emissive = material.b; // Combine color and light values vec4 color = albedo; color += ambient + diffuse + specular + emissive; // Apply light falloff float falloff = 1.0 - distance( lightPosition, position ) / lightRadius; color *= falloff; // Apply SSAO color -= vec4( 1.0 ) * ( 1.0 - ssao.r ); // Set final color gl_FragColor = color; } [/CODE]
  7. Sorry, I'm new here. Posted in wrong forum, but can't delete. Post moved here: http://www.gamedev.net/topic/634071-deferred-shading-light-accumulation-issue/