/* This file is part of Magnum. Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022 Vladimír Vondruš Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ #if defined(INSTANCED_OBJECT_ID) && !defined(GL_ES) && !defined(NEW_GLSL) #extension GL_EXT_gpu_shader4: require #endif #if defined(UNIFORM_BUFFERS) && defined(TEXTURE_ARRAYS) && !defined(GL_ES) #extension GL_ARB_shader_bit_encoding: require #endif #ifdef MULTI_DRAW #ifndef GL_ES #extension GL_ARB_shader_draw_parameters: require #else /* covers WebGL as well */ #extension GL_ANGLE_multi_draw: require #endif #endif #ifndef NEW_GLSL #define in attribute #define out varying #endif #ifndef RUNTIME_CONST #define const #endif /* Uniforms */ /* This one is for both classic and UBOs, as it's usually set globally instead of changing per-draw */ #ifdef EXPLICIT_UNIFORM_LOCATION layout(location = 0) #endif uniform lowp vec2 viewportSize; /* defaults to zero */ #ifndef UNIFORM_BUFFERS #ifdef EXPLICIT_UNIFORM_LOCATION layout(location = 1) #endif #ifdef TWO_DIMENSIONS uniform highp mat3 transformationProjectionMatrix #ifndef GL_ES = mat3(1.0) #endif ; #elif defined(THREE_DIMENSIONS) uniform highp mat4 transformationProjectionMatrix #ifndef GL_ES = mat4(1.0) #endif ; #else #error #endif #ifdef EXPLICIT_UNIFORM_LOCATION layout(location = 2) #endif uniform mediump float width #ifndef GL_ES = 1.0 #endif ; #ifdef EXPLICIT_UNIFORM_LOCATION layout(location = 3) #endif uniform mediump float smoothness #ifndef GL_ES = 0.0 #endif ; /* Uniform buffers */ #else #if DRAW_COUNT > 1 #ifdef EXPLICIT_UNIFORM_LOCATION layout(location = 1) #endif uniform highp uint drawOffset #ifndef GL_ES = 0u #endif ; #else #define drawOffset 0u #endif layout(std140 #ifdef EXPLICIT_BINDING , binding = 1 #endif ) uniform TransformationProjection { highp #ifdef TWO_DIMENSIONS /* Can't be a mat3 because of ANGLE, see DrawUniform in Phong.vert for details */ mat3x4 #elif defined(THREE_DIMENSIONS) mat4 #else #error #endif transformationProjectionMatrices[DRAW_COUNT]; }; #endif /* Inputs */ #ifdef EXPLICIT_ATTRIB_LOCATION layout(location = POSITION_ATTRIBUTE_LOCATION) #endif #ifdef TWO_DIMENSIONS in highp vec2 position; #elif defined(THREE_DIMENSIONS) in highp vec4 position; #else #error #endif #ifdef EXPLICIT_ATTRIB_LOCATION layout(location = LINE_DIRECTION_ATTRIBUTE_LOCATION) #endif #ifdef TWO_DIMENSIONS in highp vec2 direction_; #elif defined(THREE_DIMENSIONS) in highp vec3 direction_; #else #error #endif #ifdef EXPLICIT_ATTRIB_LOCATION layout(location = LINE_NEIGHBOR_DIRECTION_ATTRIBUTE_LOCATION) #endif #ifdef TWO_DIMENSIONS in highp vec2 neighborDirection_; #elif defined(THREE_DIMENSIONS) in highp vec3 neighborDirection_; #else #error #endif #ifdef VERTEX_COLOR #ifdef EXPLICIT_ATTRIB_LOCATION layout(location = COLOR_ATTRIBUTE_LOCATION) #endif in lowp vec4 vertexColor; #endif #ifdef INSTANCED_OBJECT_ID #ifdef EXPLICIT_ATTRIB_LOCATION layout(location = OBJECT_ID_ATTRIBUTE_LOCATION) #endif in highp uint instanceObjectId; #endif #ifdef INSTANCED_TRANSFORMATION #ifdef EXPLICIT_ATTRIB_LOCATION layout(location = TRANSFORMATION_MATRIX_ATTRIBUTE_LOCATION) #endif #ifdef TWO_DIMENSIONS in highp mat3 instancedTransformationMatrix; #elif defined(THREE_DIMENSIONS) in highp mat4 instancedTransformationMatrix; #else #error #endif #endif /* Outputs */ out highp vec2 centerDistanceSigned; out highp float halfSegmentLength; #ifdef VERTEX_COLOR out lowp vec4 interpolatedVertexColor; #endif #ifdef INSTANCED_OBJECT_ID flat out highp uint interpolatedInstanceObjectId; #endif #ifdef MULTI_DRAW flat out highp uint drawId; #endif /* Same as Math::Vector2::perpendicular() */ vec2 perpendicular(vec2 a) { return vec2(-a.y, a.x); } void main() { #ifdef UNIFORM_BUFFERS #ifdef MULTI_DRAW drawId = drawOffset + uint( #ifndef GL_ES gl_DrawIDARB /* Using GL_ARB_shader_draw_parameters, not GLSL 4.6 */ #else gl_DrawID #endif ); #else #define drawId drawOffset #endif #ifdef TWO_DIMENSIONS highp const mat3 transformationProjectionMatrix = mat3(transformationProjectionMatrices[drawId]); #elif defined(THREE_DIMENSIONS) highp const mat4 transformationProjectionMatrix = transformationProjectionMatrices[drawId]; #else #error #endif #endif #ifdef TWO_DIMENSIONS const vec2 lineCenterPosition = (transformationProjectionMatrix* #ifdef INSTANCED_TRANSFORMATION instancedTransformationMatrix* #endif vec3(position, 1.0)).xy; // TODO take prev/next positions, this makes no sense const vec2 direction = (transformationProjectionMatrix* #ifdef INSTANCED_TRANSFORMATION instancedTransformationMatrix* #endif vec3(position + direction_, 1.0)).xy - lineCenterPosition; const vec2 neighborDirection = (transformationProjectionMatrix* #ifdef INSTANCED_TRANSFORMATION instancedTransformationMatrix* #endif vec3(position + neighborDirection_, 1.0)).xy - lineCenterPosition; const float directionLength = length(direction); // TODO since this is used just for AA, set to a special value in case of // a line joint that shouldn't be AAd? halfSegmentLength = length(direction*0.5*viewportSize/2.0); // TODO zero-sized lines better? const vec2 directionNormalized = directionLength == 0.0 ? vec2(1.0, 0.0) : direction/directionLength; /* Line width includes also twice the smoothness radius, some extra padding on top, and is rounded to whole pixels. So for the edge distance we need half of it. */ // TODO ref the paper here; actually just drop all that, smoothstep FTW const float edgeDistance = ceil(width + 2.0*smoothness)*0.5; /* Copied from MeshTools::generateLines() internals for completenes. The position is always either `A` or `B` for all four quad corners, the `d` comes in the direction attribute, `pd`/`nd` in neighborDirection and the vertex order, which is (4n +) 0/1/2/3, in gl_VertexID. 0-d->-------2-d-> | / \ A---------B nd | / \ v 1-d->---3-d-> \ \ \ . nd . . v C . */ // TODO redo all this here /* The perpendicular direction is rotating 90° counterclockwise. Which means for points 1 and 3 (i.e., gl_VertexID not divisible by 2) we need to negate it to point the other way. */ // TODO zero-sized lines do what? const float edgeSign = (gl_VertexID & 1) == 0 ? 1.0 : -1.0; const float capSign = (gl_VertexID & 2) == 0 ? -1.0 : 1.0; const float edgeDistanceSigned = edgeDistance*edgeSign; // vec2 edgeDirection = perpendicular(directionNormalized)*edgeDistanceSigned*2.0/viewportSize; // float centerDirection vec2 edgeDirection; /* Distance to center, passed to the fragment shader. It's chosen in a way that interpolates to a zero vector in the quad center, and the area where `abs(centerDirection) <= [d+w,w]` is inside the line. Inside the line strip (where there's no line caps, shown on the left) the X value is always 0, resulting in no antialiasing done on the beginning/end edge in order to join tightly with the neigboring segments. 0------------------2 0-----------------------------2 [0,+w]-------------[0,+w] [-d-w,+w]------------------[+d+w,+w] | | | | | | [0,0] [0,0] [0,0] [-d-w,0] [0,0] [+d+w,0] | | | | | | [0,-w]-------------[0,-w] [-d-w,-w]------------------[+d+w,-w] 1------------------3 1-----------------------------3 */ // TODO handle caps centerDistanceSigned.y = edgeDistanceSigned; /* If the neighbor direction is a NaN, it means we're at the line cap -- the quad gets extended beyond A or B in the direction of the segment, as shown with the points 0 and 1: 0--+--- | | | A--d->-- | | 1--+--- For points 0 and 1 it'll be in the negative direction `d`, for points 2 and 3 in positive `d`. */ if(all(isnan(neighborDirection))) { edgeDirection = (directionNormalized*capSign + perpendicular(directionNormalized)*edgeSign)*edgeDistance*2.0/viewportSize ; centerDistanceSigned.x = (edgeDistance + halfSegmentLength)*capSign; /* Otherwise we need to create a tight joint with the neighboring line segment, as shown with the points 2 and 3. Given normalized direction `d` and neighbor direction `nd`, `normalized(d + nd)` is the "average" direction of the two and `perpendicular(normalized(d + nd))` gives us the direction from B to 2: --------+----2 | / alpha/2 w | / j |/ --d->-B alpha/2 / \ / nd / v ----3 With `alpha` being the angle between `d` and `nd`, `alpha/2` appears in two right triangles and the following holds, `w` being the edge distance from above, and `j` being the length that's needed to scale `perpendicular(normalized(d + nd))` to get point 2: |d + nd| w 2 w sin(alpha/2) = -------- = --- --> j = -------- 2 |d| j |d + nd| Point 3 is then just in the opposite direction; for the other side it's done equivalently. */ } else { // edgeDirection = perpendicular(directionNormalized)*edgeSign*edgeDistance*2.0/viewportSize; const vec2 averageDirection = capSign*directionNormalized + normalize(neighborDirection); const float averageDirectionLength = length(averageDirection); edgeDirection = perpendicular(averageDirection)*(capSign*edgeSign*edgeDistance*4.0/averageDirectionLength)/viewportSize; // const float ex = sqrt((4.0*edgeDistance*edgeDistance/(averageDirectionLength*averageDirectionLength)) - edgeDistance*edgeDistance); const float ex = sqrt(dot(edgeDirection, edgeDirection) - edgeDistance*edgeDistance); // edgeDirection = -perpendicular(averageDirection)*(1.0*edgeDistance*edgeSign*capSign/averageDirectionLength) // *2.0/viewportSize; // TODO it can't be 0!! it also has to include the skew in here but // then somehow be marked to not smooth centerDistanceSigned.x = halfSegmentLength*capSign;// + ex*sign(dot(direction*capSign, edgeDirection)); } // TODO cap ends / joints, depending on neighborDirection size gl_Position.xyzw = vec4(lineCenterPosition + edgeDirection, 0.0, 1.0); #elif defined(THREE_DIMENSIONS) // TODO 3D, how to handle perspective? multiply edgeDistance with w? gl_Position = transformationProjectionMatrix* #ifdef INSTANCED_TRANSFORMATION instancedTransformationMatrix* #endif position; #else #error #endif #ifdef VERTEX_COLOR /* Vertex colors, if enabled */ interpolatedVertexColor = vertexColor; #endif #ifdef INSTANCED_OBJECT_ID /* Instanced object ID, if enabled */ interpolatedInstanceObjectId = instanceObjectId; #endif }