Hello Oliver, Le 04/08/2018 à 11:20, oliver a écrit : > Jack wrote: >> For me, the simplest way to achieve this, is to use a mesh square with >> shaders. Take a look at exemples in Gem and shaders and how to move >> vertices in model view. > > Hi, Jack ! thanks a lot for your suggestion. > > Unfortunately my my shader/glsl skills are very limited and so is the > documentation of [mesh_square] or [glsl_vertex]... > > [mesh_square]-help just says: > "This object is usefull when working with vertex_shader." > > do you (or anybody here) know any example patches that demonstrate the > approach to creating an arbitrary plane with [mesh_square] ?
Yes, there is an exemple in Gem : 10.glsl/09.vertex_texture_fetching In this exemple, the Z position of each vertex of a mesh_square depends on the color of the texture. > > (the GLSL example patches don't really seem to be pointing that out.) See above. > > i also tried the geometry help patch from GEM examples, but this gives > me an error: > > [glsl_geometry]: compile Info_log: > [glsl_geometry]: ERROR: 0:17: 'gl_VerticesIn' : undeclared identifier Using geometry is possible here with [gemVertexbuffer] but it is more complicated. Attached is an exemple (not perfect) with a vertex shader and a fragment shader with [mesh_square]. ++ Jack > > > > best > > oliver > > >> ++ >> >> Jack >> >> >> Le 03/08/2018 à 17:02, oliver a écrit : >>> Hi, dear list ! >>> >>> I am looking for a Geo, that looks like a distorted plane, in particular >>> a "concave" or "convex" plane as shown in this .jpg: >>> >>> https://wolke.klingt.org/index.php/s/QO7Vb5UDNn42CG9 >>> >>> can anybody hint me to a way that this can be done in Gem ? >>> >>> the "convex" version seems easier, it's more or less a scaled cylinder, >>> but i can't ssem to achieve the "concave" version with this Geo. >>> >>> Best >>> >>> Oliver >>> >>> >> >> >> _______________________________________________ >> Pd-list@lists.iem.at mailing list >> UNSUBSCRIBE and account-management -> >> https://lists.puredata.info/listinfo/pd-list >> > >
mesh_deformation.pd
Description: application/extension-pd
#define PI 3.1415926535897932384626433832795 uniform float deformation; varying vec4 vertColor; void main() { vertColor = gl_Color; vec4 pos_vertex = gl_Vertex; float sign = sign(pos_vertex.y); float add_y = cos(pos_vertex.x * PI * 0.5) * deformation; pos_vertex.y += add_y * sign; gl_Position = gl_ModelViewProjectionMatrix * pos_vertex; }
varying vec4 vertColor; void main() { gl_FragColor = vertColor; }
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