void main()
{
//Copy the input vertex coordinates to three output variables
//These will stay the same for every output vertex (i.e. all over the primitive)
quad0 = gl_in[0].gl_Position.xy;
quad1 = gl_in[1].gl_Position.xy;
quad2 = gl_in[2].gl_Position.xy;
//Find the bounds of the input triangle
vec2 pmin = min( quad0, min( quad1, quad2 ));
vec2 pmax = max( quad0, max( quad1, quad2 ));
//Transform and round to grid space
pmin = floor( (pmin - gridOrigin) / cellSize );
pmax = ceil( (pmax - gridOrigin) / cellSize );
//Transform into [-1,1] normalized coordinates (glViewport will transform back)
pmin = (pmin / gridSize) * 2.0 - vec2(1.0);
pmax = (pmax / gridSize) * 2.0 - vec2(1.0);
//Emit triangle strip forming the bounding box
gl_Position = vec4( pmin.x, pmin.y, 0, 1 ); EmitVertex();
gl_Position = vec4( pmax.x, pmin.y, 0, 1 ); EmitVertex();
gl_Position = vec4( pmin.x, pmax.y, 0, 1 ); EmitVertex();
gl_Position = vec4( pmax.x, pmax.y, 0, 1 ); EmitVertex();
EndPrimitive();
}
void main()
{
//Copy the input vertex coordinates to three output variables
//These will stay the same for every output vertex (i.e. all over the primitive)
quad0 = gl_in[0].gl_Position.xy;
quad1 = gl_in[1].gl_Position.xy;
quad2 = gl_in[2].gl_Position.xy;
//Get object pointer and grid info
int *ptrObj = ptrObjects + objectId * NODE_SIZE_OBJINFO;
ivec2 objGridOrigin = ivec2( ptrObj[0], ptrObj[1] );
//Find the bounds of the input triangle
vec2 gridMin = min( quad0, min( quad1, quad2 ));
vec2 gridMax = max( quad0, max( quad1, quad2 ));
//Transform and round to grid space
gridMin = floor( (gridMin - gridOrigin) / cellSize );
gridMax = ceil( (gridMax - gridOrigin) / cellSize );
quadMin = ivec2( gridMin );
//Extend left side to object boundary
gridMin.x = objGridOrigin.x;
//Transform into [-1,1] normalized coordinates (glViewport will transform back)
gridMin = (gridMin / gridSize) * 2.0 - vec2(1.0);
gridMax = (gridMax / gridSize) * 2.0 - vec2(1.0);
//Emit triangle strip forming the bounding box
gl_Position = vec4( gridMin.x, gridMin.y, 0, 1 ); EmitVertex();
gl_Position = vec4( gridMax.x, gridMin.y, 0, 1 ); EmitVertex();
gl_Position = vec4( gridMin.x, gridMax.y, 0, 1 ); EmitVertex();
gl_Position = vec4( gridMax.x, gridMax.y, 0, 1 ); EmitVertex();
EndPrimitive();
}
void main(){
for(int layer = 0; layer < maxlight; layer++){
gl_Layer = layer;
for(int i = 0; i < gl_in.length(); i++){
Geom.worldpos = lightsview[i] * gl_in[i].gl_Position;
gl_Position = lightsproj[i] * Geom.worldpos;
Geom.z = gl_Position.z/gl_Position.w;
EmitVertex();
}
EndPrimitive();
}
}
void main(){
//input line coordinates
vec2 p0 = gl_PositionIn[0].xy;
vec2 p1 = gl_PositionIn[1].xy;
//generate 50 lines and distort with perlin noise
for (int i = 0; i < 50; i++){
float x0 = snoise(vec4(p0 *3.0, time * 0.5 + 12.4, i));
float y0 = snoise( vec4( p0 * 3.0, time * 0.5 + 304.2, i ) );
float x1 = snoise( vec4( p1 * 3.0, time * 0.5 + 20.1, i ) );
float y1 = snoise( vec4( p1 * 3.0, time * 0.5 + 43.6, i ) );
vec2 q0 = p0 + vec2( x0, y0 ) * 25.0;
vec2 q1 = p1 + vec2( x1, y1 ) * 25.0;
//calculate color
vec4 color = vec4(0.0);
vec2 delta = q1 - q0;
float len = distance( delta, vec2( 0.0 ) );
if ( len > 0 ) {
int n = int( len ) + 1;
delta /= n;
for (int i=0; i<n; i++) {
color += texture2DRect( texture, q0 + delta * i );
}
color /= n;
}
color.a *= 0.4; //Making output color transparent
//output line
gl_Position = gl_ModelViewProjectionMatrix * vec4(q0, 0.0, 1.0);
gl_FrontColor = color; //0 - left color, 1 - right color
EmitVertex();
gl_Position = gl_ModelViewProjectionMatrix * vec4(q1, 0.0, 1.0);
gl_FrontColor = color; //0 - left color, 1 - right color
EmitVertex();
EndPrimitive();
}
}
void main(void) \n\
{ \n\
int i = 0; \n\
transform( gl_Position, gl_PositionIn[i], vOrder[i] ); \n\
EmitVertex(); \n\
\n\
transform( gl_Position, gl_PositionIn[i+1], vOrder[i+1] ); \n\
EmitVertex(); \n\
\n\
vec4 diff = vec4( vNormal[i]*vThickness[i], gl_PositionIn[i+1].w ); \n\
transform( gl_Position, gl_PositionIn[i+1] + diff, \n\
vOrder[i+1] ); \n\
EmitVertex(); \n\
\n\
transform( gl_Position, gl_PositionIn[i] + diff, \n\
vOrder[i] ); \n\
EmitVertex(); \n\
\n\
transform( gl_Position, gl_PositionIn[i], vOrder[i] ); \n\
EmitVertex(); \n\
EndPrimitive(); \n\
} \n";
void main() {
// Pick one of the endpoints, and translate
// it to the origin in the x,y plane.
mat4 trans =
mat4 (1, 0, 0, -gl_in[0].gl_Position.x,
0, 1, 0, -gl_in[0].gl_Position.y,
0, 0, 1, 0,
0, 0, 0, 1);
// Inverse translation
mat4 transInv =
mat4 (1, 0, 0, gl_in[0].gl_Position.x,
0, 1, 0, gl_in[0].gl_Position.y,
0, 0, 1, 0,
0, 0, 0, 1);
vec4 pos[6];
pos[2] = gl_in[0].gl_Position; // At (x,y) origin
pos[3] = gl_in[1].gl_Position; // Not at (x,y) origin
float width = 0.5;
mat4 moveUp =
mat4(1, 0, 0, 0,
0, 1, 0, width,
0, 0, 1, 0,
0, 0, 0, 1);
mat4 moveDown =
mat4(1, 0, 0, 0,
0, 1, 0, -width,
0, 0, 1, 0,
0, 0, 0, 1);
#if 0
// Rotate about the z-axis to get the line
// into the x / z plane. Actually, we know
// what the end result of that rotation will
// look like without performing the rotation,
// all that is need to be known is the length
// of the line.
//
// What is needed is the inverse of the
// rotation matrix to rotate the new points
// back into their original basis
float cosTheta;
float sinTheta;
float d = sqrt(pos[3].x * pos[3].x + pos[3].y * pos[3].y);
pos[3].y = 0;
if(pos[1].x >= 0 && pos[1].y >= 0) {
sinTheta = pos[1].y / d;
cosTheta = pos[1].x / d;
pos[3].x = d;
}
if(pos[1].x < 0 && pos[1].y >= 0) {
// Make sin(theta) -sin(theta) for
// the inv rotation. -cos(theta) = cos(theta)
sinTheta = -pos[1].y / d;
cosTheta = -pos[1].x / d;
pos[3].x = -d;
}
if(pos[1].x < 0 && pos[1].y < 0) {
sinTheta = -pos[1].y / d;
cosTheta = -pos[1].x / d;
pos[3].x = -d;
pos[3].y = 0;
}
if(pos[1].x >= 0 && pos[1].y < 0) {
// Make sin(theta) -sin(theta) for
// the inv rotation. -cos(theta) = cos(theta)
sinTheta = pos[1].y / d;
cosTheta = pos[1].x / d;
pos[3].x = d;
}
mat4 rotInv =
mat4 (cosTheta, sinTheta, 0, 0,
sinTheta, cosTheta, 0, 0,
0, 0, 1, 0,
0, 0, 0, 1);
vec4 width = vec4(0, 0.5, 0, 0) * 0.1;
pos[0] = pos[2] + width;
pos[4] = pos[2] - width;
pos[1] = pos[3] + width;
pos[5] = pos[3] - width;
// Emit transformed vertices
for(int i = 0; i < 6; i++)
{
// Transform the vertex into the view plane
gl_Position = proj * transInv * pos[i];
// Set the out color for this vertex
vertexColor = geomColor[i];
// Emit the vertex
EmitVertex();
}
#endif
gl_Position = proj * transInv * pos[2];
vertexColor = geomColor[0];
EmitVertex();
gl_Position = proj * transInv * pos[3];
vertexColor = geomColor[1];
EmitVertex();
// Done composing the primitive
EndPrimitive();
}
ShaderCode GenerateGeometryShaderCode(APIType ApiType, const geometry_shader_uid_data* uid_data)
{
ShaderCode out;
// Non-uid template parameters will write to the dummy data (=> gets optimized out)
const unsigned int vertex_in = uid_data->primitive_type + 1;
unsigned int vertex_out = uid_data->primitive_type == PRIMITIVE_TRIANGLES ? 3 : 4;
if (uid_data->wireframe)
vertex_out++;
if (ApiType == APIType::OpenGL || ApiType == APIType::Vulkan)
{
// Insert layout parameters
if (g_ActiveConfig.backend_info.bSupportsGSInstancing)
{
out.Write("layout(%s, invocations = %d) in;\n", primitives_ogl[uid_data->primitive_type],
uid_data->stereo ? 2 : 1);
out.Write("layout(%s_strip, max_vertices = %d) out;\n",
uid_data->wireframe ? "line" : "triangle", vertex_out);
}
else
{
out.Write("layout(%s) in;\n", primitives_ogl[uid_data->primitive_type]);
out.Write("layout(%s_strip, max_vertices = %d) out;\n",
uid_data->wireframe ? "line" : "triangle",
uid_data->stereo ? vertex_out * 2 : vertex_out);
}
}
out.Write("%s", s_lighting_struct);
// uniforms
if (ApiType == APIType::OpenGL || ApiType == APIType::Vulkan)
out.Write("UBO_BINDING(std140, 3) uniform GSBlock {\n");
else
out.Write("cbuffer GSBlock {\n");
out.Write("\tfloat4 " I_STEREOPARAMS ";\n"
"\tfloat4 " I_LINEPTPARAMS ";\n"
"\tint4 " I_TEXOFFSET ";\n"
"};\n");
out.Write("struct VS_OUTPUT {\n");
GenerateVSOutputMembers<ShaderCode>(out, ApiType, uid_data->numTexGens, uid_data->pixel_lighting,
"");
out.Write("};\n");
if (ApiType == APIType::OpenGL || ApiType == APIType::Vulkan)
{
if (g_ActiveConfig.backend_info.bSupportsGSInstancing)
out.Write("#define InstanceID gl_InvocationID\n");
out.Write("VARYING_LOCATION(0) in VertexData {\n");
GenerateVSOutputMembers<ShaderCode>(
out, ApiType, uid_data->numTexGens, uid_data->pixel_lighting,
GetInterpolationQualifier(uid_data->msaa, uid_data->ssaa, true, true));
out.Write("} vs[%d];\n", vertex_in);
out.Write("VARYING_LOCATION(0) out VertexData {\n");
GenerateVSOutputMembers<ShaderCode>(
out, ApiType, uid_data->numTexGens, uid_data->pixel_lighting,
GetInterpolationQualifier(uid_data->msaa, uid_data->ssaa, false, true));
if (uid_data->stereo)
out.Write("\tflat int layer;\n");
out.Write("} ps;\n");
out.Write("void main()\n{\n");
}
else // D3D
{
out.Write("struct VertexData {\n");
out.Write("\tVS_OUTPUT o;\n");
if (uid_data->stereo)
out.Write("\tuint layer : SV_RenderTargetArrayIndex;\n");
out.Write("};\n");
if (g_ActiveConfig.backend_info.bSupportsGSInstancing)
{
out.Write("[maxvertexcount(%d)]\n[instance(%d)]\n", vertex_out, uid_data->stereo ? 2 : 1);
out.Write("void main(%s VS_OUTPUT o[%d], inout %sStream<VertexData> output, in uint "
"InstanceID : SV_GSInstanceID)\n{\n",
primitives_d3d[uid_data->primitive_type], vertex_in,
uid_data->wireframe ? "Line" : "Triangle");
}
else
{
out.Write("[maxvertexcount(%d)]\n", uid_data->stereo ? vertex_out * 2 : vertex_out);
out.Write("void main(%s VS_OUTPUT o[%d], inout %sStream<VertexData> output)\n{\n",
primitives_d3d[uid_data->primitive_type], vertex_in,
uid_data->wireframe ? "Line" : "Triangle");
}
out.Write("\tVertexData ps;\n");
}
if (uid_data->primitive_type == PRIMITIVE_LINES)
{
if (ApiType == APIType::OpenGL || ApiType == APIType::Vulkan)
{
out.Write("\tVS_OUTPUT start, end;\n");
AssignVSOutputMembers(out, "start", "vs[0]", uid_data->numTexGens, uid_data->pixel_lighting);
AssignVSOutputMembers(out, "end", "vs[1]", uid_data->numTexGens, uid_data->pixel_lighting);
}
else
{
out.Write("\tVS_OUTPUT start = o[0];\n");
out.Write("\tVS_OUTPUT end = o[1];\n");
}
// GameCube/Wii's line drawing algorithm is a little quirky. It does not
// use the correct line caps. Instead, the line caps are vertical or
// horizontal depending the slope of the line.
out.Write("\tfloat2 offset;\n"
"\tfloat2 to = abs(end.pos.xy / end.pos.w - start.pos.xy / start.pos.w);\n"
// FIXME: What does real hardware do when line is at a 45-degree angle?
// FIXME: Lines aren't drawn at the correct width. See Twilight Princess map.
"\tif (" I_LINEPTPARAMS ".y * to.y > " I_LINEPTPARAMS ".x * to.x) {\n"
// Line is more tall. Extend geometry left and right.
// Lerp LineWidth/2 from [0..VpWidth] to [-1..1]
"\t\toffset = float2(" I_LINEPTPARAMS ".z / " I_LINEPTPARAMS ".x, 0);\n"
"\t} else {\n"
// Line is more wide. Extend geometry up and down.
// Lerp LineWidth/2 from [0..VpHeight] to [1..-1]
"\t\toffset = float2(0, -" I_LINEPTPARAMS ".z / " I_LINEPTPARAMS ".y);\n"
"\t}\n");
}
else if (uid_data->primitive_type == PRIMITIVE_POINTS)
{
if (ApiType == APIType::OpenGL || ApiType == APIType::Vulkan)
{
out.Write("\tVS_OUTPUT center;\n");
AssignVSOutputMembers(out, "center", "vs[0]", uid_data->numTexGens, uid_data->pixel_lighting);
}
else
{
out.Write("\tVS_OUTPUT center = o[0];\n");
}
// Offset from center to upper right vertex
// Lerp PointSize/2 from [0,0..VpWidth,VpHeight] to [-1,1..1,-1]
out.Write("\tfloat2 offset = float2(" I_LINEPTPARAMS ".w / " I_LINEPTPARAMS
".x, -" I_LINEPTPARAMS ".w / " I_LINEPTPARAMS ".y) * center.pos.w;\n");
}
if (uid_data->stereo)
{
// If the GPU supports invocation we don't need a for loop and can simply use the
// invocation identifier to determine which layer we're rendering.
if (g_ActiveConfig.backend_info.bSupportsGSInstancing)
out.Write("\tint eye = InstanceID;\n");
else
out.Write("\tfor (int eye = 0; eye < 2; ++eye) {\n");
}
if (uid_data->wireframe)
out.Write("\tVS_OUTPUT first;\n");
out.Write("\tfor (int i = 0; i < %d; ++i) {\n", vertex_in);
if (ApiType == APIType::OpenGL || ApiType == APIType::Vulkan)
{
out.Write("\tVS_OUTPUT f;\n");
AssignVSOutputMembers(out, "f", "vs[i]", uid_data->numTexGens, uid_data->pixel_lighting);
if (g_ActiveConfig.backend_info.bSupportsDepthClamp &&
DriverDetails::HasBug(DriverDetails::BUG_BROKENCLIPDISTANCE))
{
// On certain GPUs we have to consume the clip distance from the vertex shader
// or else the other vertex shader outputs will get corrupted.
out.Write("\tf.clipDist0 = gl_in[i].gl_ClipDistance[0];\n");
out.Write("\tf.clipDist1 = gl_in[i].gl_ClipDistance[1];\n");
}
}
else
{
out.Write("\tVS_OUTPUT f = o[i];\n");
}
if (uid_data->stereo)
{
// Select the output layer
out.Write("\tps.layer = eye;\n");
if (ApiType == APIType::OpenGL || ApiType == APIType::Vulkan)
out.Write("\tgl_Layer = eye;\n");
// For stereoscopy add a small horizontal offset in Normalized Device Coordinates proportional
// to the depth of the vertex. We retrieve the depth value from the w-component of the projected
// vertex which contains the negated z-component of the original vertex.
// For negative parallax (out-of-screen effects) we subtract a convergence value from
// the depth value. This results in objects at a distance smaller than the convergence
// distance to seemingly appear in front of the screen.
// This formula is based on page 13 of the "Nvidia 3D Vision Automatic, Best Practices Guide"
out.Write("\tfloat hoffset = (eye == 0) ? " I_STEREOPARAMS ".x : " I_STEREOPARAMS ".y;\n");
out.Write("\tf.pos.x += hoffset * (f.pos.w - " I_STEREOPARAMS ".z);\n");
}
if (uid_data->primitive_type == PRIMITIVE_LINES)
{
out.Write("\tVS_OUTPUT l = f;\n"
"\tVS_OUTPUT r = f;\n");
out.Write("\tl.pos.xy -= offset * l.pos.w;\n"
"\tr.pos.xy += offset * r.pos.w;\n");
out.Write("\tif (" I_TEXOFFSET "[2] != 0) {\n");
out.Write("\tfloat texOffset = 1.0 / float(" I_TEXOFFSET "[2]);\n");
for (unsigned int i = 0; i < uid_data->numTexGens; ++i)
{
out.Write("\tif (((" I_TEXOFFSET "[0] >> %d) & 0x1) != 0)\n", i);
out.Write("\t\tr.tex%d.x += texOffset;\n", i);
}
out.Write("\t}\n");
EmitVertex(out, uid_data, "l", ApiType, true);
EmitVertex(out, uid_data, "r", ApiType);
}
else if (uid_data->primitive_type == PRIMITIVE_POINTS)
{
out.Write("\tVS_OUTPUT ll = f;\n"
"\tVS_OUTPUT lr = f;\n"
"\tVS_OUTPUT ul = f;\n"
"\tVS_OUTPUT ur = f;\n");
out.Write("\tll.pos.xy += float2(-1,-1) * offset;\n"
"\tlr.pos.xy += float2(1,-1) * offset;\n"
"\tul.pos.xy += float2(-1,1) * offset;\n"
"\tur.pos.xy += offset;\n");
out.Write("\tif (" I_TEXOFFSET "[3] != 0) {\n");
out.Write("\tfloat2 texOffset = float2(1.0 / float(" I_TEXOFFSET
"[3]), 1.0 / float(" I_TEXOFFSET "[3]));\n");
for (unsigned int i = 0; i < uid_data->numTexGens; ++i)
{
out.Write("\tif (((" I_TEXOFFSET "[1] >> %d) & 0x1) != 0) {\n", i);
out.Write("\t\tll.tex%d.xy += float2(0,1) * texOffset;\n", i);
out.Write("\t\tlr.tex%d.xy += texOffset;\n", i);
out.Write("\t\tur.tex%d.xy += float2(1,0) * texOffset;\n", i);
out.Write("\t}\n");
}
out.Write("\t}\n");
EmitVertex(out, uid_data, "ll", ApiType, true);
EmitVertex(out, uid_data, "lr", ApiType);
EmitVertex(out, uid_data, "ul", ApiType);
EmitVertex(out, uid_data, "ur", ApiType);
}
else
{
EmitVertex(out, uid_data, "f", ApiType, true);
}
out.Write("\t}\n");
EndPrimitive(out, uid_data, ApiType);
if (uid_data->stereo && !g_ActiveConfig.backend_info.bSupportsGSInstancing)
out.Write("\t}\n");
out.Write("}\n");
return out;
}
inline void EmitPoint(float cx, float cy, float cz, float siz) {
Vec3 centerTex(cx,cy,cz);
Vec3 centerPosition = centerTex * 32.0 - Vec3(16.0);
siz*=0.5;
normal = Vec3(0,0,-1, 0);
texFace = Vec3(0,0,0,0);
pos = centerPosition + siz* Vec3(-1, -1, -1);
EmitVertex();
texFace = Vec3(1,0,0,0);
pos = centerPosition + siz* Vec3(1, -1, -1);
EmitVertex();
texFace = Vec3(0,1,0,0);
pos = centerPosition + siz* Vec3(-1, 1, -1);
EmitVertex();
texFace = Vec3(1,1,0,0);
pos = centerPosition + siz* Vec3(1, 1, -1);
EmitVertex();
EndPrimitive();
normal = Vec3(0,0,1, 0);
texFace = Vec3(0,0,0,0);
pos = centerPosition + siz* Vec3(-1, -1, 1);
EmitVertex();
texFace = Vec3(1,0,0,0);
pos = centerPosition + siz* Vec3(1, -1, 1);
EmitVertex();
texFace = Vec3(0,1,0,0);
pos = centerPosition + siz* Vec3(-1, 1, 1);
EmitVertex();
texFace = Vec3(1,1,0,0);
pos = centerPosition + siz* Vec3(1, 1, 1);
EmitVertex();
EndPrimitive();
normal = Vec3(-1,0,0, 0);
texFace = Vec3(0,0,0,0);
pos = centerPosition + siz* Vec3(-1, -1, -1);
EmitVertex();
texFace = Vec3(1,0,0,0);
pos = centerPosition + siz* Vec3(-1, -1, 1);
EmitVertex();
texFace = Vec3(0,1,0,0);
pos = centerPosition + siz* Vec3(-1, 1, -1);
EmitVertex();
texFace = Vec3(1,1,0,0);
pos = centerPosition + siz* Vec3(-1, 1, 1);
EmitVertex();
EndPrimitive();
normal = Vec3(1,0,0, 0);
texFace = Vec3(0,0,0,0);
pos = centerPosition + siz* Vec3(1, -1, -1);
EmitVertex();
texFace = Vec3(1,0,0,0);
pos = centerPosition + siz* Vec3(1, -1, 1);
EmitVertex();
texFace = Vec3(0,1,0,0);
pos = centerPosition + siz* Vec3(1, 1, -1);
EmitVertex();
texFace = Vec3(1,1,0,0);
pos = centerPosition + siz* Vec3(1, 1, 1);
EmitVertex();
EndPrimitive();
normal = Vec3(0,1,0, 0);
texFace = Vec3(0,0,0,0);
pos = centerPosition + siz* Vec3(-1, 1, -1);
EmitVertex();
texFace = Vec3(1,0,0,0);
pos = centerPosition + siz* Vec3(-1, 1, 1);
EmitVertex();
texFace = Vec3(0,1,0,0);
pos = centerPosition + siz* Vec3(1, 1, -1);
EmitVertex();
texFace = Vec3(1,1,0,0);
pos = centerPosition + siz* Vec3(1, 1, 1);
EmitVertex();
EndPrimitive();
normal = Vec3(0,-1,0, 0);
texFace = Vec3(0,0,0,0);
pos = centerPosition + siz* Vec3(-1, -1, -1);
EmitVertex();
texFace = Vec3(1,0,0,0);
pos = centerPosition + siz* Vec3(-1, -1, 1);
EmitVertex();
texFace = Vec3(0,1,0,0);
pos = centerPosition + siz* Vec3(1, -1, -1);
EmitVertex();
texFace = Vec3(1,1,0,0);
pos = centerPosition + siz* Vec3(1, -1, 1);
EmitVertex();
EndPrimitive();
}
void main()
{
mat4 matModelViewProjection = matrixCameraToClip * matrixModelToCamera;
// how large (in meters) is one cell?
vec3 cellSize = vec3(
(boundingBoxMax.x - boundingBoxMin.x) / gridCellCount.x,
(boundingBoxMax.y - boundingBoxMin.y) / gridCellCount.y,
(boundingBoxMax.z - boundingBoxMin.z) / gridCellCount.z
);
// Given the cell hash (=gl_PrimitiveIDIn), whats the 3d-grid-coordinate of the cell's center?
// This is the reverse of particleskernel.cu -> calcGridHash(int3 gridCell).
ivec3 gridCellCoordinate = ivec3(
floor(mod(gl_PrimitiveIDIn, gridCellCount.x)),
floor(mod(gl_PrimitiveIDIn, gridCellCount.x * gridCellCount.y) / gridCellCount.x),
floor(mod(gl_PrimitiveIDIn, gridCellCount.x * gridCellCount.y * gridCellCount.z) / (gridCellCount.x * gridCellCount.y))
);
vec3 posCenterOfCell = vec3(
boundingBoxMin.x + (cellSize.x * gridCellCoordinate.x) + (cellSize.x / 2.0),
boundingBoxMin.y + (cellSize.y * gridCellCoordinate.y) + (cellSize.y / 2.0),
boundingBoxMin.z + (cellSize.z * gridCellCoordinate.z) + (cellSize.z / 2.0)
);
vec4 cameraPosition = inverse(matrixModelToCamera) * vec4(0,0,0,1);
vec3 toCamera = normalize(cameraPosition.xyz - posCenterOfCell);
float quadSize = min(min(cellSize.x/2, cellSize.y/2),cellSize.z/2) * quadSizeFactor;
vec3 upWorld = vec3(0.0, 1.0, 0.0);
vec3 right = normalize(-cross(toCamera, upWorld)) * quadSize;
vec3 up = normalize(cross(toCamera, normalize(-right))) * quadSize;
// Don't draw completely transparent boxes. For some reason, this also fixes the problem of the quads disappearing at certain viewing-angles.
if(cellvalue[0] == 0.0) return;
float alpha = cellvalue[0];
if(alphaExponentiation != 1.0) alpha = pow(alpha, alphaExponentiation);
if(alpha < 1.0 && alpha > 0.993) alpha = 0.4; // show dilated cells with obvious difference.
if(alpha > 1.0) alpha = 1.0;
alpha *= alphaMultiplication;
//if(cellvalue[0] > 0) alpha = 1.0;
vec4 outColor = fixedColor;
outColor.a = alpha;
// bottom left
posCenterOfCell -= right;
posCenterOfCell -= up;
gl_Position = matModelViewProjection * vec4(posCenterOfCell, 1.0);
//texureCoordinate = vec2(-1.0, -1.0);
colorGS_to_FS = outColor;
EmitVertex();
// top left
posCenterOfCell += up*2;
gl_Position = matModelViewProjection * vec4(posCenterOfCell, 1.0);
//texureCoordinate = vec2(-1.0, 1.0);
colorGS_to_FS = outColor;
EmitVertex();
// bottom right
posCenterOfCell -= up*2;
posCenterOfCell += right * 2;
gl_Position = matModelViewProjection * vec4(posCenterOfCell, 1.0);
//texureCoordinate = vec2(1.0, -1.0);
colorGS_to_FS = outColor;
EmitVertex();
// top right
posCenterOfCell += up*2;
gl_Position = matModelViewProjection * vec4(posCenterOfCell, 1.0);
//texureCoordinate = vec2(1.0, 1.0);
colorGS_to_FS = outColor;
EmitVertex();
EndPrimitive();
}