129 lines
7.8 KiB
Text
129 lines
7.8 KiB
Text
# ============================================================================
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# sky.ludic — the HDRI sky and its image-based lighting: the equirect radiance
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# map (RGB16F, mipped), the sun found in it, a diffuse-convolved irradiance map,
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# a GGX-prefiltered map per roughness level (a 2D array), and the split-sum
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# BRDF lookup. All convolved on the GPU at load.
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# ============================================================================
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const SKY_PREFILTER_LEVELS: int = 6
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# The yaw to bake the light at the first time (radians, float bits). A game that turns the sky at
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# start sets it before r3d_init, so the image-based light is baked once at that yaw rather than at
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# 0 and then again - which is what sky_set_yaw at boot used to cost.
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# turn the HDRI so its sun sits at world azimuth `yaw` (radians, 0 = toward -z)
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function sky_set_yaw(render3d_st: mut Render3dState, yaw: float) -> void {
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sky_set_rot(render3d_st, yaw)
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# world sun = rotY(sun_hdri, -yaw): the lookup rotates a world direction by +yaw
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let s = render3d_st.sun_hdri
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v3_set(render3d_st.sun_dir, render3d_st.sky_rot_c * s[0] - render3d_st.sky_rot_s * s[2], s[1], render3d_st.sky_rot_s * s[0] + render3d_st.sky_rot_c * s[2])
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# the light is already baked at this yaw: turning to it again bakes nothing
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if render3d_st.sky_baked and yaw == render3d_st.sky_baked_yaw { return }
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sky_precompute(render3d_st)
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}
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# turn only the visible sky image (cheap, per frame): the light and the convolved
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# maps stay where they are — daylight.ludic moves those on its own terms
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function sky_set_rot(render3d_st: mut Render3dState, yaw: float) -> void {
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render3d_st.sky_yaw = yaw
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render3d_st.sky_rot_s = Math.sin(yaw); render3d_st.sky_rot_c = Math.cos(yaw)
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}
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function sky_bind_rot(render3d_st: mut Render3dState, prog: int) -> void { u_f2(render3d_st, gpu_uniform(render3d_st, prog, "u_sky_rot"), render3d_st.sky_rot_s, render3d_st.sky_rot_c) }
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# direction for an equirect uv (matches equirectUV in lighting.glsl)
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function sky_dir_from_uv(o: floats, u: float, v: float) -> void {
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let phi = (u - 0.5) * (2.0 * PI)
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let theta = v * PI
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let st = Math.sin(theta)
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v3_set(o, st * Math.sin(phi), Math.cos(theta), -(st * Math.cos(phi)))
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}
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function sky_load(render3d_st: mut Render3dState, path: string) -> bool {
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render3d_st.sky_tex = tex_load_hdr(render3d_st, path)
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if render3d_st.sky_tex == 0 { return false }
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render3d_st.sky_w = render3d_st.tex_w; render3d_st.sky_h = render3d_st.tex_h
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render3d_st.sun_dir = floats(3)
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render3d_st.sun_hdri = floats(3)
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sky_dir_from_uv(render3d_st.sun_hdri, float(render3d_st.hdr_max_x * 2 + 1) / float(render3d_st.sky_w * 2), float(render3d_st.hdr_max_y * 2 + 1) / float(render3d_st.sky_h * 2))
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v3_copy(render3d_st.sun_dir, render3d_st.sun_hdri)
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render3d_st.sky_rot_c = 1.0
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# the sun's irradiance is what the IBL clip leaves out of the map; lighting it
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# directly with that keeps sun and sky in the photograph's own proportion
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render3d_st.sun_color = v3_new(render3d_st.hdr_sun_r * render3d_st.sky_sun_boost, render3d_st.hdr_sun_g * render3d_st.sky_sun_boost, render3d_st.hdr_sun_b * render3d_st.sky_sun_boost)
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print(`sun irradiance: {fixed(render3d_st.hdr_sun_r)} {fixed(render3d_st.hdr_sun_g)} {fixed(render3d_st.hdr_sun_b)} (Q16.16), clip {fixed(render3d_st.hdr_clip)}`)
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print(`sky: {render3d_st.sky_w}x{render3d_st.sky_h}, sun at texel {render3d_st.hdr_max_x},{render3d_st.hdr_max_y}`)
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render3d_st.sky_fullscreen = mesh_fullscreen(render3d_st)
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if render3d_st.sky_start_yaw != 0.0 { sky_set_yaw(render3d_st, render3d_st.sky_start_yaw) } else { sky_precompute(render3d_st) }
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return true
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}
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function sky_convolve(render3d_st: mut Render3dState, prog: int, target_tex: int, layer: int, w: int, h: int, rough: float) -> void {
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let fbo = gpu_fb_new(render3d_st)
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gpu_fb_bind(render3d_st, fbo)
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if layer < 0 { gpu_fb_color(render3d_st, 0, target_tex) }
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else { gpu_fb_color_layer(render3d_st, 0, target_tex, layer) }
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gpu_viewport(render3d_st, 0, 0, w, h)
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gpu_use_program(render3d_st, prog)
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r3d_bind_2d(render3d_st, prog, "u_sky", 0, render3d_st.sky_tex)
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sky_bind_rot(render3d_st, prog)
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u_f(render3d_st, gpu_uniform(render3d_st, prog, "u_sun_clip"), render3d_st.hdr_clip)
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u_f(render3d_st, gpu_uniform(render3d_st, prog, "u_rough"), rough)
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u_f(render3d_st, gpu_uniform(render3d_st, prog, "u_sky_w"), float(render3d_st.sky_w))
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mesh_draw(render3d_st, render3d_st.sky_fullscreen)
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gpu_fb_bind(render3d_st, 0)
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gpu_fb_free(render3d_st, fbo)
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}
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# the prefiltered specular's width per level (its height is half): 256, 512 or 1024. The image
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# the reflections and the rough sheen are lit from; sky_set_quality bakes it again at a new size.
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function sky_set_quality(render3d_st: mut Render3dState, w: int) -> void {
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if w < 64 or w == render3d_st.sky_prefilter_w { return }
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render3d_st.sky_prefilter_w = w
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if render3d_st.sky_irradiance != 0 { sky_precompute(render3d_st) }
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}
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function sky_precompute(render3d_st: mut Render3dState) -> void {
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gpu_depth_test(render3d_st, false)
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if render3d_st.sky_irradiance != 0 {
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gpu_tex_free(render3d_st, render3d_st.sky_irradiance)
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gpu_tex_free(render3d_st, render3d_st.sky_prefilter)
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gpu_tex_free(render3d_st, render3d_st.sky_brdf)
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}
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# irradiance: 128 x 64 equirect
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if render3d_st.sky_p_irr == 0 { render3d_st.sky_p_irr = r3d_program(render3d_st, "fullscreen.vert", "ibl_irradiance.frag", ""); render3d_st.sky_p_pre = r3d_program(render3d_st, "fullscreen.vert", "ibl_prefilter.frag", ""); render3d_st.sky_p_brdf = r3d_program(render3d_st, "fullscreen.vert", "ibl_brdf.frag", "") }
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let p_irr = render3d_st.sky_p_irr
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render3d_st.sky_irradiance = tex_target(render3d_st, 128, 64, GL_RGB16F, GL_RGB, GL_FLOAT, GL_LINEAR)
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gpu_tex_bind(render3d_st, GPU_TEX2D, render3d_st.sky_irradiance)
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gpu_tex_param(render3d_st, GPU_TEX2D, GL_TEXTURE_WRAP_S, GL_REPEAT)
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sky_convolve(render3d_st, p_irr, render3d_st.sky_irradiance, -1, 128, 64, 0.0)
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# prefiltered specular: 6 roughness levels, sky_prefilter_w x half each, as a 2D array
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let p_pre = render3d_st.sky_p_pre
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render3d_st.sky_prefilter = gpu_tex_new(render3d_st)
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gpu_tex_bind(render3d_st, GPU_TEX2D_ARRAY, render3d_st.sky_prefilter)
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gpu_tex_image3d(render3d_st, GL_RGB16F, render3d_st.sky_prefilter_w, render3d_st.sky_prefilter_w / 2, SKY_PREFILTER_LEVELS, GL_RGB, GL_FLOAT, null)
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gpu_tex_param(render3d_st, GPU_TEX2D_ARRAY, GL_TEXTURE_WRAP_S, GL_REPEAT)
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gpu_tex_param(render3d_st, GPU_TEX2D_ARRAY, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE)
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gpu_tex_param(render3d_st, GPU_TEX2D_ARRAY, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
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gpu_tex_param(render3d_st, GPU_TEX2D_ARRAY, GL_TEXTURE_MIN_FILTER, GL_LINEAR)
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for l in 0 .. SKY_PREFILTER_LEVELS {
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sky_convolve(render3d_st, p_pre, render3d_st.sky_prefilter, l, render3d_st.sky_prefilter_w, render3d_st.sky_prefilter_w / 2, float(l) / float(SKY_PREFILTER_LEVELS - 1))
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}
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# BRDF LUT
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let p_brdf = render3d_st.sky_p_brdf
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render3d_st.sky_brdf = tex_target(render3d_st, 256, 256, GL_RG16F, GL_RG, GL_FLOAT, GL_LINEAR)
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sky_convolve(render3d_st, p_brdf, render3d_st.sky_brdf, -1, 256, 256, 0.0)
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render3d_st.sky_baked = true
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render3d_st.sky_baked_yaw = render3d_st.sky_yaw
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gpu_check(render3d_st, "sky precompute")
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}
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# bind the IBL set + sun for a lit program (units 12..14)
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function sky_bind_lighting(render3d_st: mut Render3dState, prog: int) -> void {
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r3d_bind_2d(render3d_st, prog, "u_irradiance", 12, render3d_st.sky_irradiance)
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r3d_bind_tex(render3d_st, prog, "u_prefilter", 13, GPU_TEX2D_ARRAY, render3d_st.sky_prefilter)
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r3d_bind_2d(render3d_st, prog, "u_brdf", 14, render3d_st.sky_brdf)
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u_v3(render3d_st, gpu_uniform(render3d_st, prog, "u_sun_dir"), render3d_st.sun_dir)
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u_v3(render3d_st, gpu_uniform(render3d_st, prog, "u_sun_color"), render3d_st.sun_color)
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u_v3(render3d_st, gpu_uniform(render3d_st, prog, "u_cam_pos"), render3d_st.cam_pos)
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u_f(render3d_st, gpu_uniform(render3d_st, prog, "u_prefilter_levels"), float(SKY_PREFILTER_LEVELS))
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daylight_bind(render3d_st, prog)
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}
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