Sign in to follow this  

OpenGL Stopping my skybox from "Blooming out"

This topic is 1884 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

I recently made a new skybox which is brighter than my old one. I have encountered a problem where my bloom shader sees my bright skybox and blurs it beyond recognition. I somehow need to keep the effect where the bright sky bleeds onto the edges of the mountains without my sky exploding onto itself. Anyone have any idea how to prevent this?

btw. I'm using OpenGL.

Share this post

Link to post
Share on other sites
Can you post the pixelshader for your bloom effect? Is there a threshold you can increase for the blooming? It seems like many pixels in your new skybox are brighter (closer to (1,1,1,1) ) and trigger the blooming threshold because of that.

Share this post

Link to post
Share on other sites
[quote]Can you post the pixelshader for your bloom effect? Is there a threshold you can increase for the blooming? It seems like many pixels in your new skybox are brighter (closer to (1,1,1,1) ) and trigger the blooming threshold because of that.[/quote]

Yes it does have a threshold (even controllable from the in game GUI). However changing the threshold would affect everything not just the skybox. Anyway here is my code:

#version 120
uniform sampler2D color_texture;
uniform float level;
varying vec2 vTexCoord;
void main(void)
vec4 sample = texture2D(color_texture, vTexCoord);
if((0.2126*sample.r) + (0.7152*sample.g) + (0.0722*sample.b) > level)
float brightenRatio = 1.0 / max(max(sample.r, sample.g), sample.b);
sample.r *= brightenRatio;
sample.g *= brightenRatio;
sample.b *= brightenRatio;
sample.r = 0.0;
sample.g = 0.0;
sample.b = 0.0;
sample.a = (0.2126*sample.r) + (0.7152*sample.g) + (0.0722*sample.b);
gl_FragColor = sample;

I think I have a solution though, I can do a masked blend when I compose the final image and whatever pixels are skybox will not be copied onto the new image.

Share this post

Link to post
Share on other sites
Well don't use if's, because that method looks shitty. There is hard jump from black to white. This is how you make a soft threshold:
vec3 colorThresholded = max(0.0, color - vec3(threshold)) * (1.0 / threshold);

Share this post

Link to post
Share on other sites
you may want to go so far as to mask the skybox, you may use one of the channels of your GBuffer, or a stencil buffer, or something to indicate which pixels of the screens should be eligible for bloom.

blooming the sky is an intutive way to make a homogenous look to the effect. but your artists will likely want more control over what the player sees, even in the extremely bright sky.

We haven't added masking yet, but we want to. we want to mask other post effects.

Share this post

Link to post
Share on other sites
If you mask out the sky when applying the bloom, the environment will no longer blend into the sky, causing an irregularity around edges.
Can't you simply lower the brightness of the sky so it's more adjusted to the rest of the scene before blooming?

Share this post

Link to post
Share on other sites
Just set a stencil bit when you draw your skybox, and stencil test for that bit being unset when applying bloom. If you've got the same depth/stencil buffer attached, you'll apply bloom to everything else, while leaving your skybox untouched.

Share this post

Link to post
Share on other sites
Sign in to follow this  

  • Similar Content

    • By xhcao
      Does sync be needed to read texture content after access texture image in compute shader?
      My simple code is as below,
      glBindImageTexture(0, texture[0], 0, GL_FALSE, 3, GL_READ_ONLY, GL_R32UI);
      glBindImageTexture(1, texture[1], 0, GL_FALSE, 4, GL_WRITE_ONLY, GL_R32UI);
      glDispatchCompute(1, 1, 1);
      // Does sync be needed here?
      glBindFramebuffer(GL_READ_FRAMEBUFFER, framebuffer);
                                     GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, texture[1], 0);
      glReadPixels(0, 0, kWidth, kHeight, GL_RED_INTEGER, GL_UNSIGNED_INT, outputValues);
      Compute shader is very simple, imageLoad content from texture[0], and imageStore content to texture[1]. Does need to sync after dispatchCompute?
    • By Jonathan2006
      My question: is it possible to transform multiple angular velocities so that they can be reinserted as one? My research is below:
      // This works quat quaternion1 = GEQuaternionFromAngleRadians(angleRadiansVector1); quat quaternion2 = GEMultiplyQuaternions(quaternion1, GEQuaternionFromAngleRadians(angleRadiansVector2)); quat quaternion3 = GEMultiplyQuaternions(quaternion2, GEQuaternionFromAngleRadians(angleRadiansVector3)); glMultMatrixf(GEMat4FromQuaternion(quaternion3).array); // The first two work fine but not the third. Why? quat quaternion1 = GEQuaternionFromAngleRadians(angleRadiansVector1); vec3 vector1 = GETransformQuaternionAndVector(quaternion1, angularVelocity1); quat quaternion2 = GEQuaternionFromAngleRadians(angleRadiansVector2); vec3 vector2 = GETransformQuaternionAndVector(quaternion2, angularVelocity2); // This doesn't work //quat quaternion3 = GEQuaternionFromAngleRadians(angleRadiansVector3); //vec3 vector3 = GETransformQuaternionAndVector(quaternion3, angularVelocity3); vec3 angleVelocity = GEAddVectors(vector1, vector2); // Does not work: vec3 angleVelocity = GEAddVectors(vector1, GEAddVectors(vector2, vector3)); static vec3 angleRadiansVector; vec3 angularAcceleration = GESetVector(0.0, 0.0, 0.0); // Sending it through one angular velocity later in my motion engine angleVelocity = GEAddVectors(angleVelocity, GEMultiplyVectorAndScalar(angularAcceleration, timeStep)); angleRadiansVector = GEAddVectors(angleRadiansVector, GEMultiplyVectorAndScalar(angleVelocity, timeStep)); glMultMatrixf(GEMat4FromEulerAngle(angleRadiansVector).array); Also how do I combine multiple angularAcceleration variables? Is there an easier way to transform the angular values?
    • By dpadam450
      I have this code below in both my vertex and fragment shader, however when I request glGetUniformLocation("Lights[0].diffuse") or "Lights[0].attenuation", it returns -1. It will only give me a valid uniform location if I actually use the diffuse/attenuation variables in the VERTEX shader. Because I use position in the vertex shader, it always returns a valid uniform location. I've read that I can share uniforms across both vertex and fragment, but I'm confused what this is even compiling to if this is the case.
      #define NUM_LIGHTS 2
      struct Light
          vec3 position;
          vec3 diffuse;
          float attenuation;
      uniform Light Lights[NUM_LIGHTS];
    • By pr033r
      I have a Bachelor project on topic "Implenet 3D Boid's algorithm in OpenGL". All OpenGL issues works fine for me, all rendering etc. But when I started implement the boid's algorithm it was getting worse and worse. I read article ( inspirate from another code (here: but it still doesn't work like in tutorials and videos. For example the main problem: when I apply Cohesion (one of three main laws of boids) it makes some "cycling knot". Second, when some flock touch to another it scary change the coordination or respawn in origin (x: 0, y:0. z:0). Just some streng things. 
      I followed many tutorials, change a try everything but it isn't so smooth, without lags like in another videos. I really need your help. 
      My code (optimalizing branch):
      Exe file (if you want to look) and models folder (for those who will download the sources):
      Thanks for any help...

    • By Andrija
      I am currently trying to implement shadow mapping into my project , but although i can render my depth map to the screen and it looks okay , when i sample it with shadowCoords there is no shadow.
      Here is my light space matrix calculation
      mat4x4 lightViewMatrix; vec3 sun_pos = {SUN_OFFSET * the_sun->direction[0], SUN_OFFSET * the_sun->direction[1], SUN_OFFSET * the_sun->direction[2]}; mat4x4_look_at(lightViewMatrix,sun_pos,player->pos,up); mat4x4_mul(lightSpaceMatrix,lightProjMatrix,lightViewMatrix); I will tweak the values for the size and frustum of the shadow map, but for now i just want to draw shadows around the player position
      the_sun->direction is a normalized vector so i multiply it by a constant to get the position.
      player->pos is the camera position in world space
      the light projection matrix is calculated like this:
      mat4x4_ortho(lightProjMatrix,-SHADOW_FAR,SHADOW_FAR,-SHADOW_FAR,SHADOW_FAR,NEAR,SHADOW_FAR); Shadow vertex shader:
      uniform mat4 light_space_matrix; void main() { gl_Position = light_space_matrix * transfMatrix * vec4(position, 1.0f); } Shadow fragment shader:
      out float fragDepth; void main() { fragDepth = gl_FragCoord.z; } I am using deferred rendering so i have all my world positions in the g_positions buffer
      My shadow calculation in the deferred fragment shader:
      float get_shadow_fac(vec4 light_space_pos) { vec3 shadow_coords = / light_space_pos.w; shadow_coords = shadow_coords * 0.5 + 0.5; float closest_depth = texture(shadow_map, shadow_coords.xy).r; float current_depth = shadow_coords.z; float shadow_fac = 1.0; if(closest_depth < current_depth) shadow_fac = 0.5; return shadow_fac; } I call the function like this:
      get_shadow_fac(light_space_matrix * vec4(position,1.0)); Where position is the value i got from sampling the g_position buffer
      Here is my depth texture (i know it will produce low quality shadows but i just want to get it working for now):
      sorry because of the compression , the black smudges are trees ...
      EDIT: Depth texture attachment:
  • Popular Now