Hello,
I have currently got into shaders again. Now, I want some clarification.
As I have been googling, reading and all I have come to conclusion about spaces:
Origin is just something you define, like (0,1,0), it's a position from the Model's center or OpenGL coordinate center.
Model transform(M) is the so told model center's transform regarding the OpenGL coordinate center. (M*vec)
View transform(V) is the Model's transform according to camera, as the camera doesn't move and is at the (0,0,0). (V*M*vec)
Projection(P) is what projects the View to Screen. (P*V*M*vec)
(Please correct me if I am wrong.)
So now to the problem:
I am trying to implement a Deferred Rendering G-Buffer.
I have got a FBO with all the required textures: Diffuse, Depth, Normals, Position, UV(I am not using UVs in my particular sample).
The main issue starts here. I know that Diffuse and Depth are okay Out of the Box.
I need Normals and Positions in View-Space, for my SSAO implementation. I get that by multiplying normals I have calculated in my Geometry shader by Transpose Inverse View*Model matrix and packing them.
But how do I need to calculate Positions texture?
Also, are there any clarifications what exactly are: Model-Space, View-Space, Camera-Space? Are they exactly as I told?
This is my G-Buffer Shader Set:
Vertex:
#version 330
// THE FOOD CHAIN GOES LIKE THIS
// Vert
// Geom
// Frag
layout (location=0) in vec3 pos;
layout (location=6) in vec4 col;
uniform mat4 M;
uniform mat4 V;
uniform mat4 P;
out vData
{
vec4 color;
vec4 pos;
}vertex;
void main()
{
vec4 _col=vec4(col.x/255,col.y/255,col.z/255,col.w/255);
mat4 MVP = P*V*M;
vertex.color=_col;
vertex.pos=vec4(pos,1.0);
gl_Position = MVP * vec4(pos,1);
}
Geometry
#version 330
// THE FOOD CHAIN GOES LIKE THIS
// Vert
// Geom
// Frag
layout (triangles) in;
layout (triangle_strip, max_vertices=3) out;
uniform mat3 normMatrix;
uniform mat4 M;
uniform mat4 V;
uniform mat4 P;
in vData
{
vec4 color;
vec4 pos;
}vertex[];
out vec3 normal;
out vec4 color;
out vec4 position;
void main()
{
vec3 calcNorm=normalize(normMatrix*cross(vertex[1].pos.xyz - vertex[0].pos.xyz, vertex[2].pos.xyz - vertex[0].pos.xyz))*0.5+0.5;
normal = calcNorm;
color = vertex[0].color;
position = M*vertex[0].pos;
gl_Position = gl_in[0].gl_Position;
EmitVertex();
normal = calcNorm;
color = vertex[1].color;
position = M*vertex[1].pos;
gl_Position = gl_in[1].gl_Position;
EmitVertex();
normal = calcNorm;
color = vertex[2].color;
position = M*vertex[2].pos;
gl_Position = gl_in[2].gl_Position;
EmitVertex();
EndPrimitive();
}
Fragment
#version 330
// THE FOOD CHAIN GOES LIKE THIS
// Vert
// Geom
// Frag
in vec4 position;
in vec3 normal;
in vec4 color;
layout (location = 0) out vec3 Gdiffuse;
layout (location = 1) out vec3 Gnormal;
layout (location = 2) out vec3 Gposition;
layout (location = 3) out vec3 Gtexcoord;
void main(){
Gdiffuse = color.rgb;
Gnormal = normal;
Gposition = position.rgb;
Gtexcoord = vec3(0);
}
This is how it looks:
(Upper left - diffuse, Lower left - random normals for SSAO, Right - Depth, Normal, Position, UV)
( Yeah, it's a voxel engine, generic. 
But it's really fun learning to optimize and all. 
Nothing more satisfying than to see it be faster and more memory efficient. )
But it's really fun learning to optimize and all. Nothing more satisfying than to see it be faster and more memory efficient. )
your camera, with the camera position (center of projection) being the center (0,0,0).
