vec4 partTranslate = texture(partValues, vec2(partIndex_translate, partSlot));
vec4 partRotate = texture(partValues, vec2(partIndex_rotate, partSlot));

// Grab the fourth translate component as scale.
float s = partTranslate.w;
partTranslate.w = 1.0;

mat4 partMatrix = mat4(
                       vec4(s,0,0,0),
                       vec4(0,s,0,0),
                       vec4(0,0,s,0),
                       partTranslate
                       );

float yRatioScaler = yRatio > 1.0 ? 1.0 : yRatio;
float xMore = yRatio / yRatioScaler;
float yMore = 1.0 / yRatioScaler;
float zFixer = -150.0; // we flip & compress Z for the final depth write. Our world is all in RHS, negative Z from screen. Device is +Z.
// matrix is actually transpose of how it "looks" here...
mat4 projectionMatrix = mat4(xMore, 0,     0,               0,
                             0,     yMore, 0,               0,
                             0,     0,     1.0 / zFixer,    -1.0 / eyePos,
                             0,     0,     eyePos/ zFixer,  0);

// How did my old one work? It did, with I think a nonstandard scaling of W that worked out in the end.
// Switching to more conventional like http://www.songho.ca/opengl/gl_projectionmatrix.html

// dvb1601 also take a look at http://csc.lsu.edu/~kooima/pdfs/gen-perspective.pdf for offset-perspective.
//n /= 20.0;
//xMore /= 20.0;
//yMore /= 20.0;

xMore /= eyePos / zNear;
yMore /= eyePos / zNear;



projectionMatrix = mat4(zNear / yMore, 0, 0, 0,
                        0, zNear / xMore, 0, 0,
                        0, 0, -(zFar+zNear)/(zFar-zNear), -1,
                        0, 0, -2*zFar*zNear/(zFar-zNear), 0);

//partMatrix = partMatrix * rotter;
mat4 viewMatrix = cameraMatrix * partMatrix;
mat4 transformMatrix = projectionMatrix * viewMatrix;

modelPosV = pos;
vec3 t1 = rotateByQuaternion(pos, partRotate);


worldPosV = (partMatrix * vec4(t1, 1.0)).xyz;

viewPosV = (cameraMatrix * vec4(worldPosV, 1.0)).xyz;

vec4 transformedPos = projectionMatrix * vec4(viewPosV, 1.0);
gl_Position = transformedPos;