Initial commit (import old repo)HEADmain

1 files changed, 183 insertions, 0 deletions

diff --git a/shaders.ha b/shaders.ha
new file mode 100644
index 0000000..624892b
--- /dev/null
+++ b/shaders.ha
@@ -0,0 +1,183 @@
+use gl::*;
+use glw;
+use trace;
+
+let VAO_BLOCKS: uint = 0;
+let SHADER_BLOCKS: uint = 0;
+
+let VAO_GUI: uint = 0;
+let SHADER_GUI: uint = 0;
+
+fn shaders_init() void = {
+	trace::info(&trace::root, "loading shaders...");
+
+	glGenVertexArrays(1, &VAO_BLOCKS);
+	glBindVertexArray(VAO_BLOCKS);
+	glEnableVertexAttribArray(0);
+	glVertexAttribBinding(0, 0);
+	glVertexAttribFormat(0, 3, GL_UNSIGNED_SHORT, 0,
+		offset(Vertex { ... }.position): uint);
+	glEnableVertexAttribArray(1);
+	glVertexAttribBinding(1, 0);
+	glVertexAttribFormat(1, 3, GL_BYTE, 1,
+		offset(Vertex { ... }.normal): uint);
+	glEnableVertexAttribArray(2);
+	glVertexAttribBinding(2, 0);
+	glVertexAttribFormat(2, 2, GL_UNSIGNED_SHORT, 0,
+		offset(Vertex { ... }.texcoord): uint);
+	glEnableVertexAttribArray(3);
+	glVertexAttribBinding(3, 0);
+	glVertexAttribIFormat(3, 1, GL_UNSIGNED_BYTE,
+		offset(Vertex { ... }.flags): uint);
+	glBindVertexArray(0);
+
+	SHADER_BLOCKS = glCreateProgram();
+	glAttachShader(SHADER_BLOCKS, glw::compile_shader_src(
+		GL_VERTEX_SHADER,
+		"#version 310 es
+
+		layout(location = 0) uniform mat4 u_transform;
+		layout(location = 1) uniform vec3 u_position;
+		layout(location = 2) uniform float u_texcoord_scale;
+
+		layout(location = 0) in vec3 a_position;
+		layout(location = 1) in lowp vec3 a_normal;
+		layout(location = 2) in vec2 a_texcoord;
+		layout(location = 3) in lowp uint a_flags;
+
+		const lowp uint U_EXCL = 1u << 0u;
+		const lowp uint V_EXCL = 1u << 1u;
+		// the smallest value such that 1.0 - EPSILON < 1.0
+		const float EPSILON = 1.0 / float(1 << 24);
+
+		out lowp vec3 v_normal;
+		out vec2 v_texcoord;
+
+		void main() {
+			vec3 position = a_position * (1.0 / 2048.0) - 1.0 + u_position;
+			gl_Position = u_transform * vec4(position, 1.0);
+			v_normal = a_normal;
+			v_texcoord = u_texcoord_scale * a_texcoord;
+			// XXX: This fixes an issue with occassional texture
+			// bleeding at the scale of individual pixels on the
+			// bottom and right edges of a sprite, caused by the
+			// interpolated texture coordinate coming out as equal
+			// to the upper limit for that quad, which under
+			// GL_NEAREST filtering actually belongs to a texel on
+			// the wrong side of the sprite boundary.
+			//
+			// For whatever reason Mesa llvmpipe exhibits more
+			// severe rounding errors on all sprite edges, where
+			// v_texcoord in the fragment shader can be _below_ the
+			// supposed lower bound. An EPSILON of 2^-16 applied
+			// to all edges seems to be necessary in that case.
+			// I assume this to be a numerical compromise in favor
+			// of acceptable software rendering performance, but
+			// wasn't able to find a mention of it anywhere
+			// (I didn't look at the code, though), and the GL spec
+			// doesn't seem to explicitly permit it, though I well
+			// might be wrong about that.
+			//
+			// (2024 note): I am very tempted to remove all that and
+			// replace it with 'Removes Herobrine. Do not touch.'.
+			if ((a_flags & U_EXCL) != 0u) {
+				v_texcoord.x -= EPSILON;
+			}
+			if ((a_flags & V_EXCL) != 0u) {
+				v_texcoord.y -= EPSILON;
+			}
+		}
+		",
+	));
+	glAttachShader(SHADER_BLOCKS, glw::compile_shader_src(
+		GL_FRAGMENT_SHADER,
+		"#version 310 es
+
+		precision mediump float;
+
+		layout(location = 3) uniform mediump sampler2D tex_albedo;
+
+		in lowp vec3 v_normal;
+		in highp vec2 v_texcoord;
+
+		layout(location = 0) out vec4 f_color;
+
+		void main() {
+			vec4 albedo = texture(tex_albedo, v_texcoord);
+			if (albedo.a < 0.1) {
+				discard;
+			}
+			float light = 0.7
+				+ dot(vec3(0, 0.2, 0), v_normal)
+				+ abs(dot(vec3(0.1, 0, 0), v_normal));
+			f_color = vec4(light * albedo.rgb, albedo.a);
+		}
+		",
+	));
+	glw::link_program(SHADER_BLOCKS);
+	glUseProgram(SHADER_BLOCKS);
+	glUniform1f(2, 1.0 / ATLAS_BLOCKS.width: f32);
+	glUniform1i(3, 0);
+
+	glGenVertexArrays(1, &VAO_GUI);
+	glBindVertexArray(VAO_GUI);
+	glEnableVertexAttribArray(0);
+	glVertexAttribBinding(0, 0);
+	glVertexAttribFormat(0, 2, GL_FLOAT, 0,
+		offset(GuiVertex { ... }.position): uint);
+	glEnableVertexAttribArray(1);
+	glVertexAttribBinding(1, 0);
+	glVertexAttribFormat(1, 2, GL_FLOAT, 0,
+		offset(GuiVertex { ... }.texcoord): uint);
+	glEnableVertexAttribArray(2);
+	glVertexAttribBinding(2, 0);
+	glVertexAttribFormat(2, 3, GL_UNSIGNED_BYTE, 1,
+		offset(GuiVertex { ... }.color): uint);
+	glBindVertexArray(0);
+
+	SHADER_GUI = glCreateProgram();
+	glAttachShader(SHADER_GUI, glw::compile_shader_src(
+		GL_VERTEX_SHADER,
+		"#version 310 es
+
+		layout(location = 0) uniform mat4 u_transform;
+
+		layout(location = 0) in vec2 a_position;
+		layout(location = 1) in vec2 a_texcoord;
+		layout(location = 2) in vec4 a_color;
+
+		out vec2 v_texcoord;
+		out vec4 v_color;
+
+		void main() {
+			gl_Position = u_transform * vec4(a_position, 0.0, 1.0);
+			v_texcoord = a_texcoord;
+			// XXX: crude srgb for now...
+			v_color = vec4(pow(a_color.rgb, vec3(2.2)), a_color.a);
+		}
+		",
+	));
+	glAttachShader(SHADER_GUI, glw::compile_shader_src(
+		GL_FRAGMENT_SHADER,
+		"#version 310 es
+
+		precision mediump float;
+
+		layout(location = 1) uniform sampler2D tex_color;
+
+		in vec2 v_texcoord;
+		in vec4 v_color;
+
+		layout(location = 0) out vec4 f_color;
+
+		void main() {
+			f_color = v_color * texture(tex_color, v_texcoord);
+		}
+		",
+	));
+	glw::link_program(SHADER_GUI);
+	glUseProgram(SHADER_GUI);
+	glUniform1i(1, 0);
+
+	glUseProgram(0);
+};