[PD] Gem - how to get a concave/convex plane

Sun Aug 5 01:28:48 CEST 2018

cyrille henry wrote:
> hello,
> 
> you can try [curve3d]

cyrille, jack: thanks a lot for your kind help.

i tried both your suggestions with some success , but i'm not quite 
there yet.

i attached an example patch providing both methods and problems.

basically [curve3d] works well, with a minor issue that can be worked 
around. though i don't understand why it's there.

the issue is that the applied texture is rotated by 90°. i tried several 
things to correct it ([pix_flip], [pix_coordinate]) but they all messed 
up the texture.

========================================================================

the vertex-shader approach of jack produces the shape i was looking for, 
but unfortunately doesn't allow texture mapping. or at least i wasn't 
able to figure out how to do it.

thanks for any further thoughts ...

best

oliver
-------------- next part --------------
#N canvas 516 50 834 744 10;
#X declare -lib Gem -path Gem;
#X obj 8 11 cnv 15 100 60 empty empty empty 20 12 0 14 -228856 -66577
0;
#N canvas 24 469 455 304 gemwin 0;
#X obj 132 182 gemwin;
#X obj 67 89 outlet;
#X obj 67 10 inlet;
#X obj 67 41 route create;
#X msg 67 70 set destroy;
#X msg 142 68 set create;
#X msg 198 112 destroy;
#X msg 132 112 create \, 1;
#X obj 294 56 gemhead;
#X obj 294 80 world_light;
#X obj 207 134 loadbang;
#X obj 292 20 tgl 15 0 empty empty empty 17 7 0 10 -262144 -1 -1 0
1;
#X msg 207 155 lighting 1;
#X obj 173 25 loadbang;
#X connect 2 0 3 0;
#X connect 3 0 4 0;
#X connect 3 0 7 0;
#X connect 3 1 5 0;
#X connect 3 1 6 0;
#X connect 4 0 1 0;
#X connect 5 0 1 0;
#X connect 6 0 0 0;
#X connect 7 0 0 0;
#X connect 8 0 9 0;
#X connect 10 0 12 0;
#X connect 11 0 8 0;
#X connect 12 0 0 0;
#X connect 13 0 5 0;
#X restore 24 48 pd gemwin;
#X msg 24 29 destroy;
#X text 20 8 Create window:;
#X obj 126 10 loadbang;
#X msg 126 31 open Gem/examples/data/temp2.JPG, f 33;
#X obj 126 52 s img;
#X obj 8 87 cnv 15 400 330 empty empty CYRILLE'S_METHOD: 120 12 0 16
-204786 -66577 0;
#X obj 144 383 curve3d 3 3;
#X obj 144 252 pix_texture;
#X obj 154 359 r curve3d_1;
#X obj 144 228 pix_image;
#X obj 158 203 r img;
#X obj 144 285 translateXYZ 0 2.5 0, f 13;
#X obj 22 179 gemhead 100;
#X obj 22 228 pix_image;
#X obj 36 203 r img;
#X obj 22 285 translateXYZ -2.5 2.5 0, f 13;
#X obj 22 383 square 1;
#X obj 22 252 pix_texture;
#X obj 144 179 gemhead 90;
#X obj 283 383 curve3d 3 3;
#X obj 283 252 pix_texture;
#X obj 283 228 pix_image;
#X obj 297 203 r img;
#X obj 293 359 r curve3d_2;
#X obj 283 179 gemhead 80;
#X obj 283 285 translateXYZ 2.5 2.5 0, f 13;
#X obj 283 329 rotateXYZ 0 0 90;
#X text 31 127 Original Image on Square:, f 9;
#X text 125 126 Image on desired shape \, but it's rotated 90° CW.
Why ?, f 21;
#X text 281 115 Workaround: Modified Shape and finally rotated by 90°
, f 15;
#X obj 216 104 cnv 4 100 4 empty empty empty 170 12 0 16 -204786 -66577
0;
#X obj 8 418 cnv 15 400 300 empty empty empty 170 12 0 16 -159655 -66577
0;
#X msg 21 536 set 0 2 1 1 0;
#X msg 21 620 set 2 0 -1 -1 0;
#X msg 21 654 set 2 2 1 -1 0;
#X msg 21 577 set 1 1 0 0 0;
#X msg 21 560 set 1 0 -1 0 0;
#X msg 21 594 set 1 2 1 0 0;
#X msg 21 502 set 0 0 -1 1 0;
#X msg 21 637 set 2 1 0 -0.5 0;
#X msg 21 519 set 0 1 0 0.5 0;
#X obj 21 433 loadbang;
#X text 70 450 this is the shape i want:, f 13;
#X obj 21 680 s curve3d_1;
#X text 237 434 SHAPE 2:;
#X text 80 433 SHAPE 1:;
#X text 221 451 this is how i have to modify Shape 1 because of the
90° rotation., f 23;
#X obj 409 87 cnv 15 400 630 empty empty JACK'S_METHOD: 120 12 0 16
-220544 -66577 0;
#X obj 560 105 cnv 4 100 4 empty empty empty 120 12 0 16 -220544 -66577
0;
#X obj 647 13 declare -lib Gem -path Gem;
#X obj 438 222 glsl_vertex;
#X obj 438 277 glsl_fragment;
#X obj 438 418 glsl_program;
#X msg 501 349 link \$1 \$2;
#X obj 513 300 t b f;
#X obj 501 326 pack;
#X obj 525 173 loadbang;
#X msg 525 205 open vertex.vert;
#X msg 525 260 open vertex.frag;
#X msg 528 401 deformation \$1;
#X obj 531 382 hsl 70 15 -0.5 0.5 0 0 empty empty empty -2 -8 0 10
-262144 -1 -1 0 1;
#X obj 438 460 mesh_square 50 50;
#X obj 438 184 gemhead 70;
#X obj 660 222 glsl_vertex;
#X obj 660 277 glsl_fragment;
#X obj 660 418 glsl_program;
#X obj 660 576 mesh_square 50 50;
#X obj 660 184 gemhead 60;
#X msg 723 348 link \$1 \$2;
#X obj 735 299 t b f;
#X obj 723 325 pack;
#X obj 660 539 translateXYZ 0 -2.5 0, f 13;
#X obj 660 514 pix_texture;
#X obj 660 490 pix_image;
#X obj 674 465 r img;
#X text 425 118 works perfectly well on it's own:, f 17;
#X text 648 116 but a texture can not be applied upon the mesh_square
..., f 19;
#X msg 21 455 bang;
#X msg 179 536 set 0 2 1 1 0;
#X msg 179 620 set 2 0 -1 -1 0;
#X msg 179 654 set 2 2 1 -1 0;
#X msg 179 577 set 1 1 0 0 0;
#X msg 179 502 set 0 0 -1 1 0;
#X obj 179 433 loadbang;
#X msg 179 455 bang;
#X obj 179 680 s curve3d_2;
#X msg 179 519 set 0 1 0 1 0;
#X msg 179 637 set 2 1 0 -1 0;
#X msg 179 560 set 1 0 -0.5 0 0;
#X msg 179 594 set 1 2 0.5 0 0;
#X text 438 627 Do the shader files need to be adapted to allow for
texture mapping ? or is a gemframebuffer needed ?, f 52;
#X obj 526 435 t b;
#X text 553 434 init;
#X connect 1 0 2 0;
#X connect 2 0 1 0;
#X connect 4 0 5 0;
#X connect 5 0 6 0;
#X connect 9 0 13 0;
#X connect 10 0 8 0;
#X connect 11 0 9 0;
#X connect 12 0 11 0;
#X connect 13 0 8 0;
#X connect 14 0 15 0;
#X connect 15 0 19 0;
#X connect 16 0 15 0;
#X connect 17 0 18 0;
#X connect 19 0 17 0;
#X connect 20 0 11 0;
#X connect 22 0 27 0;
#X connect 23 0 22 0;
#X connect 24 0 23 0;
#X connect 25 0 21 0;
#X connect 26 0 23 0;
#X connect 27 0 28 0;
#X connect 28 0 21 0;
#X connect 34 0 45 0;
#X connect 35 0 45 0;
#X connect 36 0 45 0;
#X connect 37 0 45 0;
#X connect 38 0 45 0;
#X connect 39 0 45 0;
#X connect 40 0 45 0;
#X connect 41 0 45 0;
#X connect 42 0 45 0;
#X connect 43 0 79 0;
#X connect 52 0 53 0;
#X connect 52 1 57 0;
#X connect 53 0 54 0;
#X connect 53 1 56 0;
#X connect 54 0 63 0;
#X connect 54 1 93 0;
#X connect 55 0 54 0;
#X connect 56 0 57 0;
#X connect 56 1 57 1;
#X connect 57 0 55 0;
#X connect 58 0 59 0;
#X connect 58 0 60 0;
#X connect 59 0 52 0;
#X connect 59 0 65 0;
#X connect 60 0 53 0;
#X connect 60 0 66 0;
#X connect 61 0 54 0;
#X connect 61 0 67 0;
#X connect 62 0 61 0;
#X connect 64 0 52 0;
#X connect 65 0 66 0;
#X connect 65 1 72 0;
#X connect 66 0 67 0;
#X connect 66 1 71 0;
#X connect 67 0 75 0;
#X connect 69 0 65 0;
#X connect 70 0 67 0;
#X connect 71 0 72 0;
#X connect 71 1 72 1;
#X connect 72 0 70 0;
#X connect 73 0 68 0;
#X connect 74 0 73 0;
#X connect 75 0 74 0;
#X connect 76 0 75 0;
#X connect 79 0 40 0;
#X connect 79 0 42 0;
#X connect 79 0 34 0;
#X connect 79 0 38 0;
#X connect 79 0 37 0;
#X connect 79 0 39 0;
#X connect 79 0 35 0;
#X connect 79 0 41 0;
#X connect 79 0 36 0;
#X connect 80 0 87 0;
#X connect 81 0 87 0;
#X connect 82 0 87 0;
#X connect 83 0 87 0;
#X connect 84 0 87 0;
#X connect 85 0 86 0;
#X connect 86 0 84 0;
#X connect 86 0 88 0;
#X connect 86 0 80 0;
#X connect 86 0 90 0;
#X connect 86 0 83 0;
#X connect 86 0 91 0;
#X connect 86 0 81 0;
#X connect 86 0 89 0;
#X connect 86 0 82 0;
#X connect 88 0 87 0;
#X connect 89 0 87 0;
#X connect 90 0 87 0;
#X connect 91 0 87 0;
#X connect 93 0 62 0;
-------------- next part --------------
varying vec4 vertColor;

void main() {
  gl_FragColor = vertColor;
}
-------------- next part --------------
#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;
}