workshopsoft/ludic
2
0
Fork 0
Code Issues Pull requests Projects Releases 26 Packages Wiki Activity Actions

fix(render3d): water read the window's size, not the frame it drew into

Browse source 
The water shader's `u_screen`, and the reflection target's size, were both taken
from gl_w/gl_h - the drawable. But gl_FragCoord in that shader runs over the
scene target, which is post_w x post_h. They match only at a render scale of 1;
at anything less the refraction and depth reads landed in the wrong corner of
the frame and the lake showed a squashed copy of it instead of its own bed.

Both now come from the scene target. The reflection is sized from it too, which
also stops it paying for pixels the water never samples. R3D_DUMP_REFL reads the
target's own w/h rather than recomputing them.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
This commit is contained in:
Orkun ÇAKILKAYA 2026-09-10 16:15:34 +03:00
parent 9c00cd3e44
commit 9ba093bf07
1 changed files with 10 additions and 3 deletions
Download patch file Download diff file Expand all files Collapse all files

13
packages/ludic.render3d/water.ludic
View file

@ -24,7 +24,10 @@ function water_reflection_pass() -> void {
if water_refl == null {
if Os.has_env("R3D_REFLDIV") { water_refl_div = Text.to_int(Os.env("R3D_REFLDIV")) }
if water_refl != null { target_free(water_refl) }
water_refl = target_new(gl_w / water_refl_div, gl_h / water_refl_div, GL_RGBA16F, GL_RGBA, GL_HALF_FLOAT, true, GL_LINEAR)
# sized from the scene target, not the window: with a render scale below 1 the frame
# this reflection is composited into is smaller than the drawable, and a reflection
# rendered at the window's size would be paying for pixels the water never samples
water_refl = target_new(post_w / water_refl_div, post_h / water_refl_div, GL_RGBA16F, GL_RGBA, GL_HALF_FLOAT, true, GL_LINEAR)
water_saved = words(16 * 4 + 3)
}
# save the camera
@ -67,7 +70,7 @@ function water_reflection_pass() -> void {
sc_skip_blade = sb
sc_freeze = false
gl_cull_face(GL_BACK)
if Os.has_env("R3D_DUMP_REFL") and not water_dumped { water_dumped = true; tex_dump(water_refl.color, gl_w / water_refl_div, gl_h / water_refl_div, "build/dbg_refl.ppm") }
if Os.has_env("R3D_DUMP_REFL") and not water_dumped { water_dumped = true; tex_dump(water_refl.color, water_refl.w, water_refl.h, "build/dbg_refl.ppm") }
# restore
r3d_clip_y = 0xCF000000
m4_copy(cam_view, water_saved)
@ -96,7 +99,11 @@ function water_draw(depth_tex: int) -> void {
u_f(gl_uniform(p, "u_level"), water_level)
u_f2(gl_uniform(p, "u_center"), water_cx, water_cz)
u_f2(gl_uniform(p, "u_extent"), water_ex, water_ez)
u_f2(gl_uniform(p, "u_screen"), fi(gl_w), fi(gl_h))
# gl_FragCoord here runs over the scene target, which is post_w x post_h — not the
# window. They are the same size only at a render scale of 1; at anything less, taking
# the window's size sent the refraction and depth reads into the wrong corner of the
# frame, and the lake showed a squashed copy of it instead of its own bed.
u_f2(gl_uniform(p, "u_screen"), fi(post_w), fi(post_h))
var ron = F_ZERO
if water_refl != null {
# bind on its own unit first: generating the mip chain re-binds the texture on the active unit,