What's a good fixed way for motion blur that doesn't look like a lazy buffer effect?
Doom3 BFG supposedly does a nice multipass motion blur using player velocity and angle differences but the viewmodel is excluded which kind of breaks the illusion. It also implies the blur is done in cgame.
I intend to do this to id Tech 3.
Better motion blur?
Re: Better motion blur?
I tried to make motion blur. The algorithm itself is very simple, but requires working with matrices.
effect dont work (problems with velocity vector)
effect dont work (problems with velocity vector)
Code: Select all
void R_MotionBlur (void) {
mat4_t pMVP;
unsigned defBits = 0;
int id;
if (r_newrefdef.rdflags & RDF_NOWORLDMODEL)
return;
if (r_newrefdef.rdflags & RDF_IRGOGGLES)
return;
// setup program
GL_BindProgram(motionBlurProgram, defBits);
id = motionBlurProgram->id[defBits];
qglUniformMatrix4fv(qglGetUniformLocation(id, "u_PrevModelViewProj"), 1, GL_FALSE, (const GLfloat*)pMVP);
qglUniformMatrix4fv(qglGetUniformLocation(id, "u_InverseModelViewMat"), 1, GL_FALSE, (const GLfloat*)r_newrefdef.unprojMatrix);
qglUniform2f(qglGetUniformLocation(id, "u_screenSize"), vid.width, vid.height);
GL_SelectTexture (GL_TEXTURE0_ARB);
GL_BindRect (ScreenMap->texnum);
qglCopyTexSubImage2D (GL_TEXTURE_RECTANGLE_ARB, 0, 0, 0, 0, 0, vid.width, vid.height);
qglUniform1i (qglGetUniformLocation(id, "u_ScreenTex"), 0);
GL_SelectTexture (GL_TEXTURE1_ARB);
GL_BindRect (depthMap->texnum);
qglUniform1i (qglGetUniformLocation(id, "u_DepthTex"), 1);
R_DrawFullScreenQuad();
GL_BindNullProgram();
GL_SelectTexture(GL_TEXTURE0_ARB);
Mat4_Multiply(r_newrefdef.modelViewMatrix, r_newrefdef.projectionMatrix, pMVP);
}
Code: Select all
uniform sampler2DRect u_ScreenTex;
uniform sampler2DRect u_DepthTex;
uniform mat4 u_InverseModelViewMat;
uniform mat4 u_PrevModelViewProj;
void main(void)
{
float depth = texture2DRect(u_DepthTex, gl_FragCoord.xy).r;
vec4 v = u_InverseModelViewMat * vec4(gl_FragCoord.xy, depth, 1.0);
vec3 worldPos = v.xyz / v.w;
// Current viewport position
vec4 currentPos = v;
// Use the world position, and transform by the previous view-
// projection matrix.
vec4 previousPos = vec4(worldPos, 1.0) * u_PrevModelViewProj;
// Convert to nonhomogeneous points [-1,1] by dividing by w.
previousPos /= previousPos.w;
// Use this frame's position and last frame's to compute the pixel
// velocity.
vec2 velocity = (currentPos - previousPos)/3000.0;
// Get the initial color at this pixel.
//vec4 color = vec4(0.0, 0.0, 0.0, 0.0);
//for(int i = 0; i < 16; ++i)
// {
// // Sample the color buffer along the velocity vector.
// vec4 currentColor = texture2DRect(u_ScreenTex, gl_FragCoord.xy + vec2(velocity)*i);
// // Add the current color to our color sum.
// color += currentColor;
//}
vec4 color = texture2DRect(u_ScreenTex, gl_FragCoord.xy);
vec2 texCoord = gl_FragCoord.xy;
texCoord += velocity;
for(int i = 1; i < 32; ++i, texCoord += velocity)
{
// Sample the color buffer along the velocity vector.
vec4 currentColor = texture2DRect(u_ScreenTex, texCoord);
// Add the current color to our color sum.
color += currentColor;
}
// Average all of the samples to get the final blur color.
gl_FragColor = color / 32.0;
}
Re: Better motion blur?
I never got the vector-based motion blur to work
but however, I did do a different method that does work. Sort of.
Just capturing the frames alternating between 5 screen texture buffers (which takes up a crapload of VRAM, 40MB at 1920x1080) , then mixing them in a fragment shader. It's most effective at 120-240fps.
![Image](http://leileilol.mancubus.net/crap/mblur8.jpg)
![Image](http://leileilol.mancubus.net/crap/mblur9.jpg)
Sure, I could take a gradual buffer approach, but i'm trying to retain as much color precision as I can since we already lose some with overbrights.
but however, I did do a different method that does work. Sort of.
Just capturing the frames alternating between 5 screen texture buffers (which takes up a crapload of VRAM, 40MB at 1920x1080) , then mixing them in a fragment shader. It's most effective at 120-240fps.
![Image](http://leileilol.mancubus.net/crap/mblur8.jpg)
![Image](http://leileilol.mancubus.net/crap/mblur9.jpg)
Sure, I could take a gradual buffer approach, but i'm trying to retain as much color precision as I can since we already lose some with overbrights.
i should not be here
Re: Better motion blur?
Damn) I'm thought about this method some days ago ![Smile :)](./images/smilies/icon_smile.gif)
![Smile :)](./images/smilies/icon_smile.gif)
Re: Better motion blur?
You could try accumulating frames into a HDR buffer. I guess that wouldn't balloon up so much.
As for retro stuff, maybe render 4 quarter res buffers with one pixel view offset and arrange the pixels in a screendoor pattern.
As for retro stuff, maybe render 4 quarter res buffers with one pixel view offset and arrange the pixels in a screendoor pattern.