OpenGL position from depth is wrong
- by CoffeeandCode
My engine is currently implemented using a deferred rendering technique, and today I decided to change it up a bit.
First I was storing 5 textures as so:
DEPTH24_STENCIL8 - Depth and stencil
RGBA32F - Position
RGBA10_A2 - Normals
RGBA8 x 2 - Specular & Diffuse
I decided to minimize it and reconstruct positions from the depth buffer. Trying to figure out what is wrong with my method currently has not been fun :/
Currently I get this:
which changes whenever I move the camera... weird
Vertex shader
really simple
#version 150
layout(location = 0) in vec3 position;
layout(location = 1) in vec2 uv;
out vec2 uv_f;
void main(){
uv_f = uv;
gl_Position = vec4(position, 1.0);
}
Fragment shader
Where the fun (and not so fun) stuff happens
#version 150
uniform sampler2D depth_tex;
uniform sampler2D normal_tex;
uniform sampler2D diffuse_tex;
uniform sampler2D specular_tex;
uniform mat4 inv_proj_mat;
uniform vec2 nearz_farz;
in vec2 uv_f;
... other uniforms and such ...
layout(location = 3) out vec4 PostProcess;
vec3 reconstruct_pos(){
float z = texture(depth_tex, uv_f).x;
vec4 sPos = vec4(uv_f * 2.0 - 1.0, z, 1.0);
sPos = inv_proj_mat * sPos;
return (sPos.xyz / sPos.w);
}
void main(){
vec3 pos = reconstruct_pos();
vec3 normal = texture(normal_tex, uv_f).rgb;
vec3 diffuse = texture(diffuse_tex, uv_f).rgb;
vec4 specular = texture(specular_tex, uv_f);
... do lighting ...
PostProcess = vec4(pos, 1.0); // Just for testing
}
Rendering code
probably nothing wrong here, seeing as though it always worked before
this->gbuffer->bind();
gl::Clear(gl::COLOR_BUFFER_BIT | gl::DEPTH_BUFFER_BIT);
gl::Enable(gl::DEPTH_TEST);
gl::Enable(gl::CULL_FACE);
... bind geometry shader and draw models and shiz ...
gl::Disable(gl::DEPTH_TEST);
gl::Disable(gl::CULL_FACE);
gl::Enable(gl::BLEND);
... bind textures and lighting shaders shown above then draw each light ...
gl::BindFramebuffer(gl::FRAMEBUFFER, 0);
gl::Clear(gl::COLOR_BUFFER_BIT | gl::DEPTH_BUFFER_BIT);
gl::Disable(gl::BLEND);
... bind screen shaders and draw quad with PostProcess texture ...
Rinse_and_repeat(); // not actually a function ;)
Why are my positions being output like they are?
