armory3d.armortools/armorpaint/Sources/make_particle.ts

function make_particle_run(data: material_t): node_shader_context_t {
	let context_id: string = "mesh";
	let props: shader_context_t = {
		name: context_id,
		depth_write: false,
		compare_mode: "always",
		cull_mode: "clockwise",
		vertex_elements: [
			{
				name: "pos",
				data: "short4norm"
			}
		],
		color_attachments: ["R8"]
	};
	let con_part: node_shader_context_t = node_shader_context_create(data, props);

	let vert: node_shader_t = node_shader_context_make_vert(con_part);
	let frag: node_shader_t = node_shader_context_make_frag(con_part);
	frag.ins = vert.outs;

	node_shader_write_attrib(vert, "vec4 spos = vec4(pos.xyz, 1.0);");

	node_shader_add_uniform(vert, "float brushRadius", "_brushRadius");
	node_shader_write_attrib(vert, "vec3 emitFrom = vec3(fhash(gl_InstanceID), fhash(gl_InstanceID * 2), fhash(gl_InstanceID * 3));");
	node_shader_write_attrib(vert, "emitFrom = emitFrom * brushRadius - brushRadius / 2.0;");
	node_shader_write_attrib(vert, "spos.xyz += emitFrom * vec3(256.0, 256.0, 256.0);");

	node_shader_add_uniform(vert, "mat4 pd", "_particle_data");

	let str_tex_hash: string = "float fhash(int n) { return fract(sin(float(n)) * 43758.5453); }\n";
	node_shader_add_function(vert, str_tex_hash);
	node_shader_add_out(vert, "float p_age");
	node_shader_write(vert, "p_age = pd[3][3] - float(gl_InstanceID) * pd[0][1];");
	node_shader_write(vert, "p_age -= p_age * fhash(gl_InstanceID) * pd[2][3];");

	node_shader_write(vert, "if (pd[0][0] > 0.0 && p_age < 0.0) p_age += float(int(-p_age / pd[0][0]) + 1) * pd[0][0];");

	node_shader_add_out(vert, "float p_lifetime");
	node_shader_write(vert, "p_lifetime = pd[0][2];");
	node_shader_write(vert, "if (p_age < 0.0 || p_age > p_lifetime) {");
	// write(vert, "SPIRV_Cross_Output stage_output;");
	// write(vert, "stage_output.svpos /= 0.0;");
	// write(vert, "return stage_output;");
	node_shader_write(vert, "spos /= 0.0;");
	node_shader_write(vert, "}");

	node_shader_add_out(vert, "vec3 p_velocity");
	node_shader_write(vert, "p_velocity = vec3(pd[1][0], pd[1][1], pd[1][2]);");
	node_shader_write(vert, "p_velocity.x += fhash(gl_InstanceID)                     * pd[1][3] - pd[1][3] / 2.0;");
	node_shader_write(vert, "p_velocity.y += fhash(gl_InstanceID +     int(pd[0][3])) * pd[1][3] - pd[1][3] / 2.0;");
	node_shader_write(vert, "p_velocity.z += fhash(gl_InstanceID + 2 * int(pd[0][3])) * pd[1][3] - pd[1][3] / 2.0;");
	node_shader_write(vert, "p_velocity.x += (pd[2][0] * p_age) / 5.0;");
	node_shader_write(vert, "p_velocity.y += (pd[2][1] * p_age) / 5.0;");
	node_shader_write(vert, "p_velocity.z += (pd[2][2] * p_age) / 5.0;");

	node_shader_add_out(vert, "vec3 p_location");
	node_shader_write(vert, "p_location = p_velocity * p_age;");
	node_shader_write(vert, "spos.xyz += p_location;");
	node_shader_write(vert, "spos.xyz *= vec3(0.01, 0.01, 0.01);");

	node_shader_add_uniform(vert, "mat4 WVP", "_world_view_proj_matrix");
	node_shader_write(vert, "gl_Position = mul(spos, WVP);");

	node_shader_add_uniform(vert, "vec4 inp", "_inputBrush");
	node_shader_write(vert, "vec2 binp = vec2(inp.x, 1.0 - inp.y);");
	node_shader_write(vert, "binp = binp * 2.0 - 1.0;");
	node_shader_write(vert, "binp *= gl_Position.w;");
	node_shader_write(vert, "gl_Position.xy += binp;");

	node_shader_add_out(vert, "float p_fade");
	node_shader_write(vert, "p_fade = sin(min((p_age / 8.0) * 3.141592, 3.141592));");

	node_shader_add_out(frag, "float fragColor");
	node_shader_write(frag, "fragColor = p_fade;");

	// add_out(vert, "vec4 wvpposition");
	// write(vert, "wvpposition = gl_Position;");
	// write(frag, "vec2 texCoord = wvpposition.xy / wvpposition.w;");
	// add_uniform(frag, "sampler2D gbufferD");
	// write(frag, "fragColor *= 1.0 - clamp(distance(textureLod(gbufferD, texCoord, 0.0).r, wvpposition.z), 0.0, 1.0);");

	// Material.finalize(con_part);
	con_part.data.shader_from_source = true;
	con_part.data.vertex_shader = node_shader_get(vert);
	con_part.data.fragment_shader = node_shader_get(frag);

	return con_part;
}

function make_particle_mask(vert: node_shader_t, frag: node_shader_t) {
	///if arm_physics
	if (context_raw.particle_physics) {
		node_shader_add_out(vert, "vec4 wpos");
		node_shader_add_uniform(vert, "mat4 W", "_world_matrix");
		node_shader_write_attrib(vert, "wpos = mul(vec4(pos.xyz, 1.0), W);");
		node_shader_add_uniform(frag, "vec3 particleHit", "_particleHit");
		node_shader_add_uniform(frag, "vec3 particleHitLast", "_particleHitLast");

		node_shader_write(frag, "vec3 pa = wpos.xyz - particleHit;");
		node_shader_write(frag, "vec3 ba = particleHitLast - particleHit;");
		node_shader_write(frag, "float h = clamp(dot(pa, ba) / dot(ba, ba), 0.0, 1.0);");
		node_shader_write(frag, "dist = length(pa - ba * h) * 10.0;");
		// write(frag, "dist = distance(particleHit, wpos.xyz) * 10.0;");

		node_shader_write(frag, "if (dist > 1.0) discard;");
		node_shader_write(frag, "float str = clamp(pow(1.0 / dist * brushHardness * 0.2, 4.0), 0.0, 1.0) * opacity;");
		node_shader_write(frag, "if (particleHit.x == 0.0 && particleHit.y == 0.0 && particleHit.z == 0.0) str = 0.0;");
		node_shader_write(frag, "if (str == 0.0) discard;");
		return;
	}
	///end

	node_shader_add_uniform(frag, "sampler2D texparticle", "_texparticle");
	///if (krom_direct3d11 || krom_direct3d12 || krom_metal || krom_vulkan)
	node_shader_write(frag, "float str = textureLod(texparticle, sp.xy, 0.0).r;");
	///else
	node_shader_write(frag, "float str = textureLod(texparticle, vec2(sp.x, (1.0 - sp.y)), 0.0).r;");
	///end
}