bgfx: add vector CRT renderer (#15692)

* bgfx: add vector CRT renderer

* docs: Add missing vector CRT screenshots

* Fix erroneous indent

* bgfx: enable vector CRT rendering by default. Keep -nobgfx_vectorcrt available as an explicit opt-out.

* Increase bloom targets from one-third to half resolution to prevent the blur kernel from becoming under-resolved at 1080p. Normalize blur offsets against output resolution to preserve the apparent bloom size.

* Adjust default vector bloom settings

* bgfx: improve vector CRT bloom sampling

Author: hansandersson92

bgfx/README.md

@@ -0,0 +1,12 @@
+{
+	"blend": { "equation": "add", "srcColor": "1", "dstColor": "1", "srcAlpha": "1", "dstAlpha": "1" },
+	"depth": { "function": "always", "writeenable": false },
+	"cull": { "mode": "none" },
+	"write": { "rgb": true, "alpha": true },
+	"vertex": "chains/vector-crt/vs_beam",
+	"fragment": "chains/vector-crt/fs_beam",
+	"uniforms": [
+		{ "name": "u_vector_params", "type": "vec4", "values": [ 0.016667, 0.080, 1.25, 0.14 ] },
+		{ "name": "u_target_dims", "type": "vec4", "values": [ 640.0, 480.0, 0.0015625, 0.0020833 ] }
+	]
+}

bgfx/effects/vector-crt/beam.json

@@ -0,0 +1,12 @@
+{
+	"blend": { "equation": "add", "srcColor": "1", "dstColor": "0", "srcAlpha": "1", "dstAlpha": "0" },
+	"depth": { "function": "always", "writeenable": false },
+	"cull": { "mode": "none" },
+	"write": { "rgb": true, "alpha": true },
+	"vertex": "chains/vector-crt/vs_post",
+	"fragment": "chains/vector-crt/fs_blur",
+	"uniforms": [
+		{ "name": "s_tex", "type": "int", "values": [ 0 ] },
+		{ "name": "u_blur", "type": "vec4", "values": [ 0.001, 0.0, 0.0, 0.0 ] }
+	]
+}

bgfx/effects/vector-crt/blur.json

@@ -0,0 +1,13 @@
+{
+	"blend": { "equation": "add", "srcColor": "1", "dstColor": "1", "srcAlpha": "1", "dstAlpha": "1" },
+	"depth": { "function": "always", "writeenable": false },
+	"cull": { "mode": "none" },
+	"write": { "rgb": true, "alpha": false },
+	"vertex": "chains/vector-crt/vs_post",
+	"fragment": "chains/vector-crt/fs_composite",
+	"uniforms": [
+		{ "name": "s_accum", "type": "int", "values": [ 0 ] },
+		{ "name": "s_bloom", "type": "int", "values": [ 1 ] },
+		{ "name": "u_composite", "type": "vec4", "values": [ 0.8, 1.0, 2.2, 0.1 ] }
+	]
+}

bgfx/effects/vector-crt/composite.json

@@ -0,0 +1,12 @@
+{
+	"blend": { "equation": "add", "srcColor": "1", "dstColor": "0", "srcAlpha": "1", "dstAlpha": "0" },
+	"depth": { "function": "always", "writeenable": false },
+	"cull": { "mode": "none" },
+	"write": { "rgb": true, "alpha": true },
+	"vertex": "chains/vector-crt/vs_post",
+	"fragment": "chains/vector-crt/fs_decay",
+	"uniforms": [
+		{ "name": "s_accum", "type": "int", "values": [ 0 ] },
+		{ "name": "u_decay", "type": "vec4", "values": [ 1.0, 0.0, 0.0, 0.0 ] }
+	]
+}

bgfx/effects/vector-crt/decay.json

@@ -0,0 +1,12 @@
+{
+	"blend": { "equation": "add", "srcColor": "1", "dstColor": "0", "srcAlpha": "1", "dstAlpha": "0" },
+	"depth": { "function": "always", "writeenable": false },
+	"cull": { "mode": "none" },
+	"write": { "rgb": true, "alpha": true },
+	"vertex": "chains/vector-crt/vs_post",
+	"fragment": "chains/vector-crt/fs_downsample",
+	"uniforms": [
+		{ "name": "s_accum", "type": "int", "values": [ 0 ] },
+		{ "name": "u_source_texel", "type": "vec4", "values": [ 0.0015625, 0.0020833, 0.0, 0.0 ] }
+	]
+}