Reconstruct the Object Location Based on the depth Graph

Reprinted Please note: http://blog.csdn.net/tianhai110

Reconstruct the Object Location Based on the depth Graph

Method 1: store the projection Z/W and combine x/W, Y/W to multiply the inverse matrix of the projection matrix and divide it by W to get the position of the object;

// Vertices shader code of deep pass: <br/> output. vpositioncs = MUL (input. vpositionos, g_matworldviewproj); <br/> output. vdepthcs. XY = output. vpositioncs. ZW; </P> <p> // pixel shader code for deep pass (output Z/W): <br/> return input. vdepthcs. x/input. vdepthcs. y; <br/>

 

Another delayed rendering shader

 

// Function: Convert the depth value to the vertex position of the view space <br/> // vtexcoord is the texture coordinate of the full screen quadrilateral, and x = 0 is the left side of the screen, y = 0 is the top of the screen; <br/> float3 vspositionfromdepth (float2 vtexcoord) <br/>{< br/> // obtain the depth value of this pixel <br/> float z = tex2d (depthsampler, vtexcoord ); </P> <p> // obtain x/W and Y/W based on the position of the viewport. <br/> float x = vtexcoord. x * 2-1; <br/> float y = (1-vtexcoord. y) * 2-1; </P> <p> float4 vprojectedpos = float4 (X, Y, Z, 1.0f ); </P> <p> // multiply the inverse matrix of the projection matrix <br/> float4 vpositionvs = MUL (vprojectedpos, g_matinvprojection ); </P> <p> // divide by W to obtain the vertex position <br/> return vpositionvs. XYZ/vpositionvs. w; <br/>}</P> <p>

Method 2: store the normalized view space Z as our depth. Because the depth of the view space is linear, this means that we can obtain a uniform distribution, instead of projection and Inverse Projection, to restore the vertex position. We only need to multiply the depth value by a ray pointing to the far cross section of the cone to reconstruct the vertex position.

Rendering linear depth

Void depthvs (in float4 in_vpositionos: Position, <br/> out float4 out_vpositioncs: Position, <br/> out float out_fdepthvs: texcoord0) <br/>{< br/> // calculate the position of the vertex in the view space and clip space <br/> float4x4 matworldview = MUL (g_matworld, g_matview ); <br/> float4 vpositionvs = MUL (in_vpositionos, matworldview); <br/> out_vpositioncs = MUL (vpositionvs, g_matproj); <br/> out_fdepthvs = vpositionvs. z; <br/>}</P> <p> float4 depthps (in float in_fdepthvs: texcoord0 ): color0 <br/> {<br/> // The Z value is reversed and the distance from the far cross section is exceeded (so that the depth value is between [0, 1) <br/> // (do not add a negative number to the left-hand Coordinate System) <br/> float fdepth =-in_fdepthvs/g_ffarclip; <br/> return float4 (fdepth, 1.0f, 1.0f, 1.0f); <br/>}</P> <p>

Delay shader to reconstruct vertex position

 

// Render a full-screen quadrilateral. The vertex shader is as follows: <br/> void quadvs (in float3 in_vpositionos: Position, <br/> In float3 in_vtexcoordandcornerindex: texcoord0, <br/> out float4 out_vpositioncs: Position, <br/> out float2 out_vtexcoord: texcoord0, <br/> out float3 out_vfrustumcornervs: texcoord1) <br/>{< br/> // offset position of half a pixel <br/> out_vpositioncs.x = in_vpositionos.x-(1.0f/g_vocclusiontexturesize.x); <br/> out_vpositio NCS. y = in_vpositionos.y + (1.0f/g_vocclusiontexturesize.y); <br/> out_vpositioncs.z = in_vpositionos.z; <br/> out_vpositioncs.w = 1.0f; </P> <p> // transfer the texture coordinates and the position of the cone. These vertex locations are interpolated so that the pixel shader can use rays to query the vertex locations <br/> out_vtexcoord = vertex; <br/> out_vfrustumcornervs = g_vfrustumcornersvs [vertex]; <br/>}</P> <p> // pixel shader: used to reconstruct the position in the viewspace <br/> float3 vspositionfromdepth (float2 vtexcoord, float3 vfrustumrayvs) <br/>{< br/> float fpixeldepth = tex2d (depthsampler, vtexcoord ). r; <br/> return fpixeldepth * vfrustumrayvs; <br/>}</P> <p>

G_vfrustumcornersvs is the four vertices on the far cross section of the video cone.