Hi there, following ThomasEgi idea, here is a snippet to get transparent videos in panda, the video for alpha is a red unshaded render of the video for diffuse.
files : http://dl.dropbox.com/u/13388237/Panda3D/alpha_video.zip
main class :
#####################################################
## Transparent Videos ##
#####################################################
# imports
from panda3d.core import *
loadPrcFileData('', 'dump-generated-shaders 0')
loadPrcFileData('', 'compressed-textures 0')
loadPrcFileData('', 'show-buffers 1')
loadPrcFileData('', 'basic-shaders-only 1')
import direct.directbase.DirectStart
# colors
GREY = Vec4(.2, .1, .0, .5)
BLACK = Vec4(0, 0, 0, 1)
WHITE = Vec4(1, 1, 1, 1)
# media
DIFFUSE_VIDEO = "diffuse.avi"
ALPHA_VIDEO = "alpha.avi"
MODEL = "sphere"
# shaders
VIDEO_SHADER = 'video_compositing.cg'
class Application():
def __init__(self):
# master nodes
master_scene = render.attachNewNode('scene')
master_video = render.attachNewNode('video')
master_scene.setPos(0,10,0)
master_video.setPos(0,5,0)
# 3D scene setup
model = loader.loadModel(MODEL)
model.setPos(0,0,0)
model.reparentTo(master_scene)
# video textures
diffuse_video = loader.loadTexture(DIFFUSE_VIDEO)
alpha_video = loader.loadTexture(ALPHA_VIDEO)
# cache video card
cm_cache = CardMaker("cache");
cm_cache.setUvRange(alpha_video)
card_cache = NodePath(cm_cache.generate())
card_cache.reparentTo(master_video)
card_cache.setTexture(diffuse_video)
card_cache.setTransparency(True)
ts = TextureStage('ts')
card_cache.setTexture(ts, alpha_video)
# composite video card
cm_composite = CardMaker("composite");
cm_composite.setUvRange(alpha_video)
card_composite = NodePath(cm_composite.generate())
card_composite.setShader(loader.loadShader(VIDEO_SHADER))
card_composite.setShaderInput("alpha", alpha_video)
card_composite.setShaderInput("diffuse", diffuse_video)
card_composite.setShaderInput("power", Vec3(2,0.5,0))
card_composite.setTransparency(True)
card_composite.reparentTo(master_video)
# hide unecessary card
card_cache.setAlphaScale(0)
# the 2 cards need to be at the exact same position
pos = Vec3(0,0,0)
card_cache.setPos(pos)
card_composite.setPos(pos)
app = Application()
run()shader:
//Cg
void vshader(in float4 vtx_position : POSITION,
uniform float4 texpad_diffuse,
float4 vtx_texcoord0: TEXCOORD0,
uniform float4x4 mat_modelproj,
out float4 l_position : POSITION,
out float2 l_texcoord : TEXCOORD0,
out float4 l_screenpos : TEXCOORD1)
{
l_position = mul(mat_modelproj, vtx_position);
l_texcoord = vtx_texcoord0;
l_screenpos = l_position;
}
void fshader(in float2 l_texcoord : TEXCOORD0,
in float4 l_screenpos : TEXCOORD1,
uniform sampler2D k_diffuse : TEXUNIT1,
uniform sampler2D k_alpha : TEXUNIT2,
uniform float3 k_power,
out float4 o_color : COLOR)
{
float4 diffuse = tex2D(k_diffuse, l_texcoord);
float4 alpha = tex2D(k_alpha, l_texcoord);
o_color.xyz = diffuse.xyz;
alpha.r = alpha.r*k_power.x - k_power.y;
o_color.a = alpha.r;
}